Induction of Volatile Organic Compounds of Lycopersicon esculentum Mill. and Its Resistance to Botrytis cinerea Pers. by Burdock Oligosaccharide

In the present study, we investigated the induction of volatile organic compounds （VOCs） of Lycoperslcon esculentum Mill. and its resistance to Botrytis cinerea Pers. by burdock oligosaccharlde. The disease severity of L. esculentum was evaluated 48 h after treatment with 0.6% burdock oligosaccharlde, followed by inoculation with a spore suspension of B. cinerea. The formation of O2＇, the activity of lipoxygenases （LOX）, peroxidase （POD）, cataiase （CAT）, and superoxide dismutase （SOD）, and the quantity and quallty of changes In VOCs were determined a period of time after treatment with 0.6% burdock ollgosaccharide. The results demonstrated that the disease index in treated plants was decreased by 42.5% compared with control 96 h after Inoculation. The production of O2＇ reached a maximum 6 h after treatment （1.36-fold compared with control）. There was an increase in LOX, POD, CAT and SOD activity in response to burdock oligosaccharide treatment and the enzymes showed different trends in the time-course of induction. At 120 h after treatment, （E）-2-hexenal was increased by 92% compared with control, whereas methyl salicylate showed a gradual Increase with induction period. Previous results had demonstrated that chitosan elicitor enhanced the production VOCs of L. esculentum and decreased plant susceptibility towards B. clnerea. Together, these findings suggest that increasing the production of VOCs in response to burrdock oligosaccharide may be an important mechanism for L. esculentumin its defense against pathogens, in addition, burrdock oligosaccharlde may act as a potent elicitor of resistance to disease in L. esculentum.

Proteomic Alterations of Antarctic Ice Microalga Chlamydomonas sp.Under Low-Temperature Stress

Antarctic ice microalga can survive and thrive in cold channels or pores in the Antarctic ice layer. In order to understand the adaptive mechanisms to low temperature, in the present study we compared two-dimensional polyacrylamide gel electrophoresis （2-DE） profiles of normal and low temperature-stressed Antarctic ice microalga Chlamydomonas sp. cells. In addition, new protein spots induced by low temperature were identified with peptide mass fingerprinting based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF-MS） and database searching. Well-resolved and reproducible 2-DE patterns of both normal and low temperature-stressed cells were acquired. A total of 626 spots was detected in control cells and 652 spots were detected in the corresponding low temperature-stressed cells. A total of 598 spots was matched between normal and stressed cells. Two newly synthesized proteins （a and b） in low temperature-stressed cells were characterized. Protein spot A （53 kDa, pl 6.0） was similar to isopropylmalate/homocitrate/citramalate synthases, which act in the transport and metabolism of amino acids. Protein spot b （25 kDa, pl 8.0） was related to glutathione S-transferase, which functions as a scavenger of active oxygen, free radicals, and noxious metabolites. The present study is valuable for the application of ice microalgae, establishing an ice microalga Chlamydomonas sp. proteome database, and screening molecular biomarkers for further studies.