Xianghua Wang,Maorun Fu,Xiaoqian Qu,Jingjing Liu,Jianwen Bu,Shaoran Feng,Handong Zhao,Wenxiao Jiao,Fei Sun
(E)-2-Hexenal is one of the most prevalent and abundant volatile substances in fruits. Many researchers have attempted fumigation with (E)-2-hexenal to control fungal diseases with poor or no results; the key is the inability to maintain an effective concentration for a long time. Therefore, a new starch-based antifungal coating with (E)-2-hexenal microcapsules was prepared. The obtained results showed that the microcapsule embedding rate reached 78.95% by orthogonal optimization experiments and that the (E)-2-hexenal-based coating was effective at reducing the lesion diameter of apple fruit during storage at 25 °C after Penicillium expansum infection, and in other fruits; it also achieved a good antifungal effect. Moreover, the activities of the main defense-related enzymes and the expression of key genes involved in the salicylic acid (SA) signaling pathway, such as CHI, GLU, PAL , NPR1 , and PR1 , were enhanced by (E)-2-hexenal-based coating treatment. These findings suggest that the (E)-2-hexenal-based coating has the dual effect of direct antifungal and induction of apple system resistance. E2H-based coating is a promising approach to control postharvest Penicillium expansum in fruit.
He Wang,Jingjing Li,Qian Yang,Lan Wang,Jing Wang,Yaxin Zhang,Yanjing Guo,Rui Li,Ruiqi Zhang,Xiaorong Tao,Bernal E. Valverde,Sheng Qiang,Hazem M. Kalaji,Shiguo Chen
2-Amino-3-methylhexanoic acid (AMHA) was synthetized as a non-natural amino acid more than 70 years ago; however, its possible function as an inducer of plant resistance has not been reported. Plant resistance inducers, also known as plant elicitors, are becoming a novel and important development direction in crop protection and pest management. We found that free AMHA accumulated in the mycelia but not in fermentation broths of four fungal species,Magnaporthe oryzaeand threeAlternariaspp. We unequivocally confirmed that AMHA is a naturally occurring endogenous (2S, 3S)-α-amino acid, based on isolation, purification and structural analyses. Further experiments demonstrated that AMHA has potent activity-enhancing resistance against extreme temperature stresses in several plant species. It is also highly active against fungal, bacterial and viral diseases by inducing plant resistance. AMHA pretreatment strongly protected wheat against powdery mildew,ArabidopsisagainstPseudomonas syringaeDC3000 and tobacco againstTomato spotted wilt virus. AMHA exhibits a great potential to become a unique natural elicitor protecting plants against biotic and abiotic stresses.Keywords:agricultural production;natural product;plant resistance inducer;biopesticide;biotic and abiotic stress
Songbo Lin,Yanan Dong,Xiwang Li,Yuxian Xing,Miaomiao Liu,Xiaoling Sun
Jasmonates (JAs), the group of lipid-derived hormones, were found to control the defense responses in a myriad of plants. Meaningfully, the macrolactones of 12-hydroxy jasmonate isoleucine (12OH-JA-Ile) were reported to induce the defensive response of wild tobacco. However, little to nothing has been known about the elicitation effect of JA-Ile-macrolactones on woody plants to harmful organisms, let alone its underlying mechanisms. Here, we first optimized the synthetic routine using mild toxic reagent isobutyl chloroformate instead of ethyl chloroformate for conjugation, and we used acetonitrile (MeCN) instead of ethyl alcohol for the better dissolution ofp-toluenesulfonic acid (p-TsOH) to gain JA-Ile-macrolactones. JA-Ile-macrolactone5b-treated tea plants significantly inhibited the larvae weight gain ofEctropis obliqualarvae and the lesions caused byColletotrichum camelliae. Furthermore, the expression level ofCsOPR3was significantly upregulated in5b-treated leaves. Meanwhile,5breduced the accumulation of eriodictyol 7-O-glucuronide (EDG) in tea plants, which was confirmed to promote the growth rate ofE. obliqualarvae by artificial diet assay. In conclusion, our study proved that the exogenous application of5bcould induce the tea plant resistance both to herbivoreE. obliquaand pathogenC. camelliae, and EDG was identified as one of the secondary metabolites that could influence the growth rate ofE. obliqua, but it did not directly influence the infection ofC. camelliaein vitro. Further research should be carried out to clarify the mechanism through which5binduces tea plant resistance toC. camelliae.Keywords:JA-Ile-macrolactone;induced resistance;Camellia sinensis;Ectropis obliqua;Colletotrichum camelliae
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