1 Introduction

Pyropia, formerly known as Porphyra, is the most widely consumed seaweed in the world and has been used as a food source in East Asia since ancient times. In addition to the high nutritional value, characteristic flavor,which comes from the volatile organic compounds in Pyropia, makes them more favorable.

Studies on the composition of volatile components in Pyropia as well as some other seaweeds have been conducted for decades (Whelan et al., 1982; Flament and Ohloff, 1984; Kajiwara et al., 1990; Fujimura et al., 1994;Kladi et al., 2004; Nor Ohairul Izzreen and Vijaya Ratnam, 2011; Hu et al., 2011; Ferraces-Casais et al., 2013;Yamamoto et al., 2014). More than 100 and 39 volatile compounds were identified from the dried thalli (Flament and Ohloff, 1984) and the conchocelis filaments (Kajiwara et al., 1990) of P. tenera, respectively. Using headspace solid microextraction coupled GC-MS, Hu et al.(2011) identified 44 characteristic volatile compounds from P. yezoensis, and 45 from a green mutant of P. yezoensis. These volatile compounds contain complex mixtures of aldehydes, alcohols, esters, ketones, alkenes, alkanes, and carboxylic acids.

Volatile compounds constitute the important parameters of the flavor and quality of algal products. Some volatiles endow marine algae with unique characteristic,which can be used to evaluate the quality of commercial algal products and to discriminate them from different geographical and botanical origins (Yamamoto et al.,2014). Volatile compounds may serve as pheromones,allelochemicals, and defense response chemicals against herbivores and microbes. Many volatile compounds derived from marine algae are reported to possess strong anti-viral, anti-microbial and anti-cancer activity, exhibiting potential applications in pharmaceutics and functional ingredients for both human and animals (Kajiwara et al., 2006; Akakabe and Kajiwara, 2008; Gupta and Abu-Ghannam, 2011; Neelamathi and Kannan, 2016).Moreover, volatile compounds, as the important constituents of secondary metabolites, can be induced to synthesize in response to herbivores, microbes, and biochemical stimulators such as endogenous signaling molecules, hormones, and external chemicals. In that case,fluctuations of characteristic volatile compounds may reflect the growth or development status of algae, thereby providing valuable information for mariculture management. However, till present little effort has been made to study the variation of volatile compounds in response to diverse stimuli in the commercial red algae Pyropia.

Studies on the biosynthesis of volatile compounds in marine algae have been conducted. In edible seaweeds,including Ulva, Enteromorpha, Laminaria and Porphyra(now known as Pyropia), volatile compounds were found to be synthesized via oxylipins derived from unsatuarated fatty acids (Kajiwara et al., 1996; Kajiwara et al., 1993;Boonprab et al., 2006). External stimuli, such as attacks from grazing animals and micro-organisms, and exposure to methyl jasmonate, are proved to induce the biosynthesis of oxylipins and their derivatives, thereby activating the innate defense responses (Bouarab et al., 2004;Gaquerel et al., 2007; Küpper et al., 2009).

Methyl jasmonate (MeJA) is the volatile methyl ester of jasmonic acid (JA). JA and MeJA, together with some other derivatives, are endogenous plant hormones known as jasmonates, which are reported to arise from linolenic acid in response to wound- or elicitor-induction in higher plants, and play essential roles in the regulation of systemic defense responses, growth, and development(Wasternack and Hause, 2013; Dar et al., 2015). Exposure to MeJA can enhance the production of secondary metabolites and offer protection against infection by macro- and microscopic epi- and endobionts (Zhao et al.,2005; Zeneli et al., 2006; Wasternack and Hause, 2013;Dar et al., 2015; Kumari et al., 2015). In the brown algae Laminaria digitata and Fucus vesiculosus (Küpper et al.,2009; Arnold et al., 2001), and the red algae Chondrus crispus (Bouarab et al., 2004), external MeJA treatment does trigger defense reactions, at least partially by increasing the expression and activity of biosynthetic enzymes and the synthesis of defense chemicals oxylipins(Collén et al., 2006; Gaquerel et al., 2007). However,whether and how jasmonates affect the composition and biosynthesis of volatile secondary metabolites in seaweeds remain largely unknown.

In the present study, we assessed the production of volatile substances in fresh thalli of P. yezoensis in response to external MeJA and DIECA treatment, trying to determine the influence of MeJA on volatile composition of P.yezoensis and discuss their biosynthesis fundamentally.

2 Materials and Methods

2.1 P. yezoensis Maintenance

A total of 44 volatile organic compounds were identified in untreated fresh blades of P. yezoensis, including aldehydes, alkanes, alkenes, ketones, alcohols, acids, esters, and sulfur and nitric compounds (Table 1, Control).The major components in untreated algae were alcohols(about 43.4%), alkenes (about 13.8%), acids and esters(about 17.2%), and aldehydes (about 8.8%), which accounted for more than 80% of the total volatiles detected.In particular, phytol, an acyclic diterpene alcohol that constitutes chlorophyll, was the most abundant com--pounds identified in the present study, with a relativecontent of about 37%. The second abundant compound was 3-heptadecene, with a yield of about 13%. Followed were some other compounds that yield above 2% of the total volatiles, including 2-propenoic acid-2-methyl dodecylester (about 10.32%), 2-pentadecanone (about 5.14%), n-hexadecanoic acid (about 5.19%), octadecanal(about 3.53%), 4-heptenal (about 2.65%), and isophytol(about 2.17%). β-ionone, tetradecanal, and (E, Z)-2, 6-nonadienal were also detected, although their relative contents were not so high as previously reported in P.yezoensis (Kajiwara et al., 1990, 1996; Hu et al., 2011).Among the volatiles detected, some were flavor compounds. Phytol and 3-heptadecene, two major components identified in this study, might be responsible for the flavor of P. yezoensis, as 3-heptadecene has been reported to be a characteristic flavor of marine algae (Kodamaet al., 1993). Ketones, especially long-chain unsaturated members, which have been reported as flavor components of flowers, might contribute to the pleasant smell of the algae. Benzeneacetaldehyde, with the aroma of flowers(Jürgens et al., 2003), might also contribute to the aroma of the alge. Pyrazine, a heterocyclic nitric compound with unique aromas, is often found in baked goods and may contribute to the flavor of roasted Pyropia. However,compounds with foul odor, such as dimethyl trisulfide,were also detected in the present study although the content was very limited.

式(4)中的超参数α(x)反映了分布估计对先验分布的依赖程度,α(x)越大则这种依赖越强.在实际计算时,需要对超参数α(x)进行合理地确定.

Identification of volatile compounds was made on the basis of mass spectral libraries (NIST 47, NIST 147, and Wiley 175) and data retrieved from the literature, as determined by comparisons of the retention time and molecular weight with commercial standards. Three replicates for each treatment were analyzed. Results are expressed as the mean ± standard deviation (SD). The statistical significance of treatments against control conditions was tested using the unpaired Student’s t-test.

2.2 Chemicals and Treatment

Volatile compounds were identified by GC (Varian 450-GC; Agilent Technologies, Santa Clara, CA, USA)coupled with mass spectrometry (Varian 320–MS;Agilent Technologies). Analyses were performed in the electron ionisation mode at 70 eV using a fused silica capillary column (VF-17ms, 30 m × 0.32 mm, 0.25 μm,Agilent Technologies) with a mass range of 30–500 m/z.

Since most organic volatile compounds are secondary metabolites and can be induced or inhibited to produce by external stimulations, we then studied whether external treatment with different concentration of plant hormone MeJA can affect the production of volatile compounds in P. yezoensis. As shown in Table 1, the major volatile components in untreated samples can also be detected in MeJA treated samples, but the relative contents of some components vary significantly. Higher concentrations of MeJA (50 and 100 μmol L−1) significantly lowered the content of phytol, 3-heptadecene, and 2-pentadecanone,but increased the content of 1-dodecanol, 4-heptenal, and 2-propenoic acid-2-methyl dodecylester (Table 1, P＜0.05).These results indicate that external MeJA treatment does influence the composition of volatile components in P.yezoensis.

2.3 Gas Chromatography-Mass Spectrometry Analysis of Volatile Compounds

MeJA (Sigma) was dissolved with 90% ethanol water solution to make a stock solution of 100 mmol L−1 and stored at 4℃ before use. Final concentrations of 10, 50,and 100 μmol L−1 MeJA were prepared by adding appropriate volumes of stock solution to 500 mL of sterilized seawater. Less than 0.1% of ethanol (v:v) was present in the culture medium at the maximum concentration of MeJA. Recovered fresh thalli of P. yezoensis (1.00 g)were added to a flask containing 500 mL of seawater supplemented with indicated concentration of MeJA and incubated at 20℃ for 24 h. Untreated algae were incubated for the same period of time in a culture medium containing the same quantity of ethanol as the treated algae. At least three independent experiments were conducted.

11月18日，澳大利亚动用直升机为墨尔本的四个博物馆安装2700多块太阳能电池板。这将是墨尔本最大的太阳能电池阵列。整个项目将使维多利亚州博物馆的碳排放量减少35%，每年减少4590吨二氧化碳排放。

游客们搭上列车，列车慢慢往上爬，像是要爬上喜马拉雅山区，进入一个气氛黯淡恐怖的地域，突然之间，面前出现了怒吼的雪人，列车赶紧急速后退，换上另外一条轨道，暂时似乎离开了危机，说时迟那时快，接着路上的铁轨突然中断消失了，在雪人的怒吼声中，列车急速下降，仿佛要一路掉进山谷里，中途还连续几个剧烈的翻滚……

3 Results and Discussion

3.1 Identification of Volatile Compounds in P. yezoensis

Thalli of P. yezoensis were collected from culture nets located in Dongtai County (32˚44´N, 120˚55´E), Jiangsu Province, China. The thalli were dried in the shade for 6 h and then stored at −20℃. Some frozen thalli were thawed and then incubated in sterilized seawater at 20℃ for 3 d to gain full recovery of life before performing the experiments.

Table 1 Identified volatile compounds and average content (as percent of the total intergrated peak areas)in fresh P. yezoensis treated with different concentrations of MeJA for 24 h

Note: *P ＜ 0.05 (unpaired Student’s t-test, vs control).

Compound name CAS No. Control 10 μmol L−1 50 μmol L−1 100 μmol L−1 Aldehydes 4-heptenal 6728-31-0 2.65±0.35 2.19±0.04 3.73±0.33* 3.97±0.45*Benzaldehyde 100-52-7 0.06±0.08 0.12±0.02 0.13±0.05 0.13±0.06 5-methyl-2-furancarboxaldehyde 620-02-0 0.39±0.04 0.10±0.08 0.11±0.07 0.07±0.01 Octanal 124-13-0 0.10±0.15 0.16±0.01 0.18±0.06 0.15±0.03 Benzeneacetaldehyde 122-78-1 0.28±0.06 0.45±0.03 0.72±0.01 0.53±0.01(E,Z)-2,6-nonadienal 557-48-2 0.51±0.31 0.69±0.08 0.61±0.20 0.50±0.13 2,6,6-trimethyl-1,3-cyclohexadiene-1-carboxaldehyde 116-26-7 0.25±0.15 0.42±0.07 0.32±0.06 0.37±0.08 2,6,6-trimethyl-1-cyclohexene-1-acetaldehyde 472-66-2 0.09±0.12 0.09±0.12 0.11±0.01 0.13±0.02 Tetradecanal 124-25-4 0.66±0.05 0.45±0.05 0.29±0.09 0.27±0.01 cis,cis,cis-7,10,13-hexadecatrienal 56797-43-4 0.28±0.06 0.21±0.03 0.16±0.01 0.15±0.01 Octadecanal 638-66-4 3.53±0.30 3.06±0.03* 3.12±0.51* 3.01±0.17*Alcohols Borneol 507-70-0 0.35±0.25 0.64±0.11 0.70±0.17 0.56±0.08 Trans-3-caren-2-ol 0.34±0.01 0.27±0.03 0.21±0.03 0.21±0.06 1-dodecanol 112-53-8 0.20±0.28 0.55±0.17 2.03±1.05* 10.76±7.82*4,7,7-tetramethyl-bicyclo[4,10] heptan-3-ol 16725-98-7 0.33±0.27 0.16±0.04 0.14±0.06 0.08±0.02 Cedrol 77-53-2 1.10±1.55 1.12±0.50 0.91±0.34 1.26±0.11 1-hexadecanol 36653-82-4 1.86±0.82 2.49±1.12 1.42±0.29 0.92±0.18 Isophytol 505-32-8 2.17±0.54 2.98±1.09 2.08±0.08 0.64±0.72*Phytol 150-86-7 37.09±6.11 43.35±11.48 34.95±2.80 19.17±4.09*Ketones 3,4-dimethyl-2,5-furandione 766-39-2 0.23±0.32 0.66±0.59 0.55±0.41 0.59±0.63 2-ketopiperidine 675-20-7 0.14±0.04 0.04±0.06 0.16±0.09 0.14±0.05 2-nonanone 821-55-6 0.05±0.06 0.09±0.01 0.21±0.19 0.08±0.01 5-nonen-2-one 27039-84-5 0.06±0.09 0.17±0.01 0.21±0.04 0.15±0.01 2-pentadecanone 2345-28-0 5.14±0.17 2.89±0.82* 2.54±0.46* 1.42±0.35*Alkenes 1,3-trans,5- cis-octatriene 40087-61-4 0.03±0.02 0.02±0.01 0 0.04±0.01 β-ionone 79-77-6 0.80±0.39 0.52±0.03 0.53±0.10 0.95±0.18 3-heptadecene 62026-26-0 13.00±1.91 8.10±0.95* 7.08±1.57* 7.18±0.77*Alkanes Ethoxycyclohexane 932-92-3 0.06±0.09 0.13±0.01 0.11±0.02 0.11±0.01 Tridecane 629-50-5 0.14±0.04 0.10±0.02 0.07±0.02 0.12±0.03 Heptadecane 629-78-7 1.21±1.10 0.54±0.09 0.56±0.19 0.43±0.14 Naphthalene,1,2,3,4-tetrahydro-1,1,6-trimethyl 475-03-6 0.40±0.24 0.14±0.04 0.13±0.02 0.16±0.06 Naphthalene,1,2-dihyro-1,1,6-trimethyl 30364-38-6 0.43±0.13 0.32±0.16 0.32±0.04 0.29±0.02 Acids and esters Eicosapentaenoic acid 10417-94-4 0.28±0.25 0.54±0.31 0.23±0.15 0.02±0.01 n-hexadecanoic acid 9006-59-1 5.19±1.28 6.22±2.65 4.29±0.25 4.97±1.58 Cyclohexanecarboxylic acid,3-fluorophenyl ester 78322-89-1 0.47±0.36 0.20±0.02 0.25±0.03 0.16±0.03 2-propenoic acid,2-methyl dodecylester 142-90-5 10.32±2.51 10.27±5.59 22.24±1.56* 34.78±10.32*Hexadecanoic acid methyl ester 112-39-0 0.18±0.25 0.27±0.12 0.07±0.05 0.11±0.05 4,7,10,13,16,19-docosahexaenoic acid, methyl ester 301-01-9 0.79±0.47 0.61±0.19 0.41±0.01 0.22±0.17 Sulfur and nitric compounds Dimethyl trisulfide 3658-80-8 1.38±0.05 0.91±0.13 0.76±0.14 0.67±0.18 3,5-dimethyl-1,2,4-trithiolane 23654-92-4 0.36±0.26 0.10±0.04 0 0.22±0.06 2-acetylthiazole 24295-03-2 0.07±0.02 0.20±0.09 0.37±0.21 0.16±0.02 2,5-dimethyl-pyrazine 123-32-0 0.16±0.10 0.63±0.01 0.61±0.05 0.36±0.10 2,3,5- trimethylpyrazine 14667-55-1 0.03±0.01 0.08±0.02 0.14±0.09 0.08±0.01 Hexadecanenitrile 629-79-8 0.39±0.08 0.48±0.03 0.50±0.07 0.06±0.03

Table 2 The average content of volatile compounds in fresh P. yezoensis treated with the octadecanoid pathway inhibitor DIECA

Note: *P ＜ 0.05 (unpaired Student’s t-test).

Compound name CAS No. DIECA− DIECA+Aldehydes 6728-31-0 7.75±5.78* 0.67±0.95*Benzaldehyde 100-52-7 0.30±0.20 2.89±1.02 5-methyl-2-furancarboxaldehyde 620-02-0 0.08±0.10 0.84±1.17 Octanal 124-13-0 0.16±0.03 0.21±0.29 Benzeneacetaldehyde 122-78-1 0.21±0.10 0.08±0.12(E,Z)-2,6-nonadienal 557-48-2 0.78±0.07 1.32±0.09 2,6,6-trimethyl-1,3-cyclohexadiene-1-carboxaldehyde 116-26-7 0.52±0.12 1.84±0.08 2,6,6-trimethyl-1-cyclohexene-1-acetaldehyde 472-66-2 0.12±0.10 0.91±0.04 Tetradecanal 124-25-4 3.79±0.14 2.38±0.11 cis,cis,cis-7,10,13-hexadecatrienal 56797-43-4 0.24±0.09 0.40±0.01 Octadecanal 638-66-4 11.94±0.38* 7.69±3.23*Alcohols Borneol 507-70-0 1.06±1.50 1.69±1.01 Trans-3-caren-2-ol 0.59±0.16 0.82±0.16 1-dodecanol 112-53-8 1.36±0.65* 0.05±0.06*4,7,7-tetramethyl-bicyclo[4,10] heptan-3-ol 16725-98-7 0.47±0.25 0.31±0.06 Cedrol 77-53-2 0.26±0.08 0.01±0.02 1-hexadecanol 36653-82-4 2.00±0.86 1.55±1.24 Isophytol 505-32-8 0.66±0.07* 1.74±0.52*Phytol 150-86-7 15.24±2.64* 25.60±8.15*Ketones 3,4-dimethyl-2,5-furandione 766-39-2 0.24±0.03 0.36±0.51 2-ketopiperidine 675-20-7 0.22±0.16 0.34±0.09 2-nonanone 821-55-6 0.29±0.21 0 5-nonen-2-one 27039-84-5 0.20±0.17 0.96±0.81 2-pentadecanone 2345-28-0 4.95±0.34 5.48±3.77 Alkenes 1,3-trans,5-cis-octatriene 40087-61-4 0.08±0.11 1.96±1.15 β-ionone 79-77-6 1.08±0.54 0.31±0.06 3-heptadecene 62026-26-0 18.97±5.53* 4.60±0.78*Alkanes Ethoxycyclohexane 932-92-3 0.22±0.07 0.75±1.06 Tridecane 629-50-5 0.31±0.05 0.80±0.84 Heptadecane 629-78-7 1.97±1.18 0.34±0.10 Naphthalene,1,2,3,4-tetrahydro-1,1,6-trimethyl 475-03-6 0.32±0.46 1.56±0.31 Naphthalene,1,2-dihyro-1,1,6-trimethyl 30364-38-6 0.30±0.01 0.30±0.10 Acids and esters Eicosapentaenoic acid 10417-94-4 0.06±0.08 0.45±0.64 n-hexadecanoic acid 9006-59-1 0.00 0.00 Cyclohexanecarboxylic acid,3-fluorophenyl ester 78322-89-1 0.36±0.51 1.01±0.97 2-propenoic acid, 2-methyl dodecylester 142-90-5 10.81±4.81* 5.35±0.48*Hexadecanoic acid methyl ester 112-39-0 0.00 0.59±0.84 4,7,10,13,16,19-docosahexaenoic acid, methyl ester 301-01-9 0.24±0.08 0.30±0.43 Sulfur and nitric compound Dimethyl trisulfide 3658-80-8 0.93±0.49 5.00±7.07 3,5-dimethyl-1,2,4-trithiolane 23654-92-4 0.47±0.66 0.33±0.47 2-acetylthiazole 24295-03-2 0.20±0.12 0.74±0.35 2,5-dimethyl-pyrazine 123-32-0 0.12±0.17 0.18±0.25 2,3,5- trimethylpyrazine 14667-55-1 0.24±0.34 1.61±2.28 Hexadecanenitrile 629-79-8 0.11±0.15 0.03±0.05 4-heptenal

3.2 Exogenous MeJA Treatment Influences the Composition of Volatile Components

To investigate the involvement of octadecanoid pathway in the biosynthesis of volatile compounds in P. yezoensis, recovered fresh thalli (1.00 g) were pretreated with 1 mmol L−1 diethyldithiocarbamic acid (DIECA,Sigma) for 1 h, and then transferred to fresh seawater culture medium and incubated at 20℃ for 24 h before GC-MS analysis.

In plants, phytohormone jasmonates can be synthesized endogenously through the oxylipin and the octadecanoid pathway. Enzymes involved in the biosynthesis of jasmonates from linoleic acid have been identified in several red algae, including Lithothamnion corallioides and Gracilariopsis sp. (Hamberg et al., 1992; Hamberg and Gerwick, 1993). Genome sequence studies of the brown alga Ectocarpus siliculosus also revealed candidate genes for jasmonate biosynthesis (Cock et al., 2010). Moreover,jasmonate and MeJA have been isolated from the macroalga Gelidium latifolium (Krupina and Dathe, 1991) and the unicellular green algae Dunaliella tertiolecta and D.salina (Fujii et al., 1997). Besides, MeJA has been detected in cell-free extracts of C. crispus after addition of linolenic acid (Bouarab et al., 2004). Our findings that exogenous MeJA influences the composition of volatile compounds in P. yezoensis, together with the above reports, suggest that jasmonates may be involved in regulating the biosynthesis of secondary metabolites in marine algae. Therefore, we further studied whether endogenous jasmonates may exist and be involved in the biosynthesis of volatile compounds in P. yezoensis.

After removing excessive water, the collected fresh algal samples were put into the headspace vial (20 mL, Supelco, USA) and heated at 150℃ for 20 min. The liberated volatile compounds were then directly injected (1 mL) with a split ratio of 20:1. A constant flow of chromatographic grade helium at rate of 0.8 mL min−1 was used as the carrier gas. The column temperature was initially set at 32℃ and held for 3 min and then increased to 50℃ by intervals of 5℃ min−1, held for 1 min each. The temperature was then ramped up to 200℃ in increments of 20℃ min−1 and then held for 15 min, and then finally increased, in increments of 30℃ min−1, to 270℃, which was held for 15 min.

3.3 Involvement of Octadecanoid Pathway in the Biogeneration of Volatile Compounds

Since the octadecanoid pathway is a well-characterized biosynthetic pathway for the production of jasmonates and volatile compounds, we then studied the variation of volatile components in P. yezoensis pretreated with diethyldithiocarbamic acid (DIECA), an inhibitor of the octadecanoid pathway (Farmer et al., 1994; Menke et al.,1999). Briefly, fresh blades of P. yezoensis were treated with 1 mmol L−1 DIECA for 1 h and then incubated with fresh seawater at 20℃ for 24 h before GC-MS analysis.As shown in Table 2, pretreatment with DIECA significantly decreased the content of 4-heptenal, octadecanal,3-heptadecene, and 2-propenoic acid-2-methyl dodecylester, but increased the content of phytol and isophytol.These variations were negatively correlated to those caused by external MeJA treatment (Table 1), suggesting that an internal jasmonate pathway may exist and be involved in the biosynthesis of volatile compounds in P.yezoensis. Therefore, future studies are warranted to further elucidate the biological function and biogeneration of jasmonate derivatives in P. yezoensis.

二是路面状况差。多年来在木材采伐运输过程中经重车碾压，并遭受暴雨、洪涝、严寒等灾害侵蚀，不少存在路面坑洼、路基塌陷等问题。比如，内蒙古大兴安岭国有林区80%以上为砂石路面道路甚至自然土路。

In summary, our study demonstrates that the major volatile components of P. yezoensis vary in response to external MeJA treatment. The octadecanoid pathway and endogenous jasmonates may be involved in the biosynthesis of volatile compounds in P. yezoensis. Altogether,these results provide preliminary assessment for better understanding the composition and biosynthesis of volatile compounds in P. yezoensis.

Acknowledgements

This work was supported by a grant from the PhD fellowship program of Soochow University and the National Natural Science Foundation of China (No. 41276134).

1.3.7 腹腔引流管的使用 传统组病人均常规使用腹腔引流管，并在术后腹腔引流管<50 ml/d时，予拔出腹腔引流管。ERAS组病人选择性使用腹腔引流管，并且在术后根据病人情况，尽早拔除。

References

Akakabe, Y., and Kajiwara, T., 2008. Bioactive volatile compounds from marine algae: Feeding attractants. Journal of Applied Phycology, 20 (5): 661-664.

Arnold, T. M., Targett, N. M., Tanner, C. E., Hatch, W. I., and Ferrari, K. E., 2001. Evidence for methyl jasmonate induced phlorotannin production in Fucus vesiculosus (Phaeophyceae).Journal of Phycology, 37 (6): 1026-1029.

Boonprab, K., Matsui, K., Akakabe, Y., Yoshida, M., Yotsukura,N., Chirapart, A., and Kajiwara, T., 2006. Formation of aldehyde flavor (n-hexanal, 3Z-nonenal and 2E-nonenal) in the brown alga, Laminaria angustata. Journal of Applied Phycology, 18 (3-5): 409-412.

Bouarab, K., Adas, F., Gaquerel, E., Kloareg, B., Salaün, J. P.,and Potin, P., 2004. The innate immunity of a marine red alga involves oxylipins from both the eicosanoid and octadecanoid pathways. Plant Physiology, 135 (3): 1838-1848.

Cock, J. M., Sterck, L., Rouzé, P., Scornet, D., and Allen, A. E.,2010. The Ectocarpus genome and the independent evolution of multicellularity in brown algae. Nature, 465: 617-621.

Collén, J., Hervé, C., Guisle-Marsollier, I., Leger, J., and Boyen,C., 2006. Expression profiling of Chondrus crispus (Rhodophyceae) after exposure to methyl jasmonate. Journal of Experimental Botany, 57 (14): 3869-3881.

Dar, T. A., Uddin, M., Khan, M. M. A., Hakeem, K. R., and Jaleel, H., 2015. Jasmonates counter plant stress: A review.Environmental and Experimental Botany, 115: 49-57.

Farmer, E. E., Caldelari, D., Pearce, C., Walker-Simmons, M. K.,and Ryan, C. A., 1994. Diethyldithiocarbamic acid inhibits the octadecanoid signaling pathway for the wound induction of proteinase inhibitors in tomato leaves. Plant Physiology,106 (1): 337-342.

Ferraces-Casais, P., Lage-Yusty, M. A., Rodríguez-Bernaldo de Quirós, A., and López-Hernández, J., 2013. Rapid identification of volatile compounds in fresh seaweed. Talanta, 115:798-800.

Flament, I., and Ohloff, G., 1984. Volatile constituents of algae:Odoriferous constituents of seaweeds and structure of nor-terpenoids identified in Asakusanori flavor. In: Progress in Flavor Research, Adda, J., ed., Elsevier, Amsterdam, 281-300.

Fujii, S., Yamamoto, R., Miyamoto, K., and Ueda, J., 1997.Occurrence of jasmonic acid in Dunalliela (Dunalielales,Chlorophyta). Phycological Research, 45 (4): 223-226.

Fujimura, T., Kawai, T., Kajiwara, T., and Ishida, Y., 1994.Volatile components in protoplasts isolated from the marine brown alga Dictyopteris prolifera (Dictyotales). Plant Tissue Culture Letters, 11 (1): 34-39.

Gupta, S., and Abu-Ghannam, N., 2011. Bioactive potential and possible health effects of edible brown seaweeds. Trends in Food Science & Technology, 22 (6): 315-326.

Hamberg, M., and Gerwick, W. H., 1993. Biosynthesis of vicinal dihydroxy fatty acids in the red alga Gracilariopsis lemaneiformis: Identification of a sodium-dependent 12-lipoxygenase and a hydroperoxide isomerase. Archives of Biochemistry and Biophysics, 305 (1): 115-122.

Hamberg, M., Gerwick, W. H., and Asen, P., 1992. Linoleic acid metabolism in the red alga Lithothamnion corallioides:Biosynthesis of 11(R)-hydroxy-9(Z),12(Z)-octadecadienoic acid. Lipids, 27 (7): 487-493.

Hu, C. M., Xu, J. L., Zhu, J. Y., Yan, X. J., Luo, Q. J., Yang, J.X., and Xu, P., 2011. Characteristic volatile matters in Porphyra (Bangiales). Marine Sciences, 35 (5): 106-111.

Jürgens, A., Witt, T., and Gottsberger, G., 2003. Flower scent composition in Dianthus and Saponaria species (Caryophyllaceae) and its relevance for pollination biology and taxonomy. Biochemical Systematics and Ecology, 31 (4): 345-357.

Kajiwara, T., Kashibe, M., Matsui, K., and Hatanaka, A., 1990.Volatile compounds and long-chain aldehydes formation in conchocelis-filaments of a red alga, Porphyra tenera. Phytochemistry, 29 (7): 2193-2195.

Kajiwara, T., Matsui, K., Akakabe, Y., Murakawa, T., and Arai,C., 2006. Antimicrobial browning-inhibitory effect of flavor compounds in seaweeds. Journal of Applied Phycology, 18(3-5): 413-422.

Kajiwara, T., Matsui, K., and Akakabe, Y., 1996. Biogeneration of volatile compounds via oxylipins in edible seaweeds. In:Biotechnology for Improved Foods and Flavors. Takeoka, G.R., et al., eds., American Chemical Society, Washington DC,146-166.

Kajiwara, T., Matsui, K., Hatanaka, A., Tomoi, T., Fujimura, T.,and Kawai, T., 1993. Distribution of an enzyme system producing seaweed flavor: Conversion of fatty acids to longchain aldehydes in seaweeds. Journal of Applied Phycology,5 (2): 225-230.

Kladi, M., Vagias, C., and Roussis, V., 2004. Volatile halogenated metabolites from marine red algae. Phytochemistry Reviews, 3 (3): 337-366.

Kodama, K., Kajiwara, T., Matsui, K., and Matsui, K., 1993.Volatile compounds from Japanese marine brown algae. In:Bioactive Volatile Compounds From Plants. Teranishi, R., et al., eds., Washington DC, American Chemistry Society,103-120.

Krupina, M. V., and Dathe, W., 1991. Occurrence of jasmonic acid in the red alga Gelidium latifolium. Zeitschrift für Naturforschung C, 46: 1127-1129.

Kumari, P., Reddy, C. R., and Jha, B., 2015. Methyl jasmonateinduced lipidomic and biochemical alterations in the intertidal macroalga Gracilaria dura (Gracilariaceae, Rhodophyta).Plant Cell Physiology, 56 (10): 1877-1889.

Küpper, F. C., Gaquerel, E., Cosse, A., Adas, F., Peters, A. F.,Müller, D. G., Kloareg, B., Salaün, J. P., and Potin, P., 2009.Free fatty acids and methyl jasmonate trigger defense reactions in Laminaria digitata. Plant Cell Physiology, 50 (4):789-800.

Menke, F. L. H., Parchmann, S., Mueller, M. J., Kijne, J. W.,and Memelink, J., 1999. Involvement of the octadecanoid pathway and protein phosphorylation in fungal elicitor-induced expression of terpenoid indole alkaloid biosynthetic genes in Catharanthus roseus. Plant Physiology, 119 (4):1289-1296.

Neelamathi, E., and Kannan, R., 2016. Screening and characterization of bioactive compounds of Turbinaria ornata from the gulf of Mannar, India. American-Eurasian Journal of Agricultural & Environmental Sciences, 16 (2): 243-251.

Nor Qhairul Izzreen, M. N., and Vijaya Ratnam, R., 2011. Volatile compound extraction using solid phase micro extraction coupled with gas chromatography mass spectrometry (SPMEGCMS) in local seaweeds of Kappaphycus alvarezii, Caulerpa lentillifera and Sargassum polycystem. International Food Research Journal, 18 (4): 1449-1456.

Wasternack, C., and Hause, B., 2013. Jasmonates: Biosynthesis,perception, signal transduction and action in plant stress response, growth and development. An update to the 2007 review in Annals of Botany. Annals of Botany, 111: 1021-1058.

Whelan, J., Tarafa, M. E., and Hunt, J. M., 1982. Volatile C1-C8 organic compounds in macroalgae. Nature, 299 (5878):50- 52.

Yamamoto, M., Baldermann, S., Yoshikawa, K., Fujita, A.,Mase, N., and Watanabe, N., 2014. Determination of volatile compounds in four commercial samples of Japanese green algae using solid phase microextraction gas chromatography mass spectrometry. TheScientific World Journal, 289780,DOI: 10.1155/2014/289780.

Zeneli, G., Krokene, P., Christiansen, E., Krekling, T., and Gershenzon, J., 2006. Methyl jasmonate treatment of mature Norway spruce (Picea abies) trees increases the accumulation of terpenoid resin components and protects against infection by Ceratocystis polonica, a bark beetle-associated fungus.Tree Physiology, 26 (8): 977-988.

Zhao, J., Davis, L. C., and Verpoorte, R., 2005. Elicitor signal transduction leading to production of plant secondary metabolites. Biotechnology Advances, 23 (4): 283-333.