JA-Ile-Macrolactone 5b Induces Tea Plant (Camellia sinensis) Resistance to Both Herbivore Ectropis obliqua and Pathogen Colletotrichum camelliae

Abstract

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 of p-toluenesulfonic acid (p-TsOH) to gain JA-Ile-macrolactones. JA-Ile-macrolactone 5b-treated tea plants significantly inhibited the larvae weight gain of Ectropis obliqua larvae and the lesions caused by Colletotrichum camelliae. Furthermore, the expression level of CsOPR3 was significantly upregulated in 5b-treated leaves. Meanwhile, 5b reduced the accumulation of eriodictyol 7-O-glucuronide (EDG) in tea plants, which was confirmed to promote the growth rate of E. obliqua larvae by artificial diet assay. In conclusion, our study proved that the exogenous application of 5b could induce the tea plant resistance both to herbivore E. obliqua and pathogen C. camelliae, and EDG was identified as one of the secondary metabolites that could influence the growth rate of E. obliqua, but it did not directly influence the infection of C. camelliae in vitro. Further research should be carried out to clarify the mechanism through which 5b induces tea plant resistance to C. camelliae.

Indole primes defence signalling and increases herbivore resistance in tea plants

“…Ca 2+ , MPKs, WRKYs and JA are well‐known regulators of plant resistance to chewing herbivores (Erb & Reymond, 2019; Kanchiswamy et al, 2010; Liu, Li, Xu, Wang, & Lou, 2018; Vadassery et al, 2012; Wu, Hettenhausen, Meldau, & Baldwin, 2007). Flavonoids, phenolamides, phenolic acids, and purine alkaloids are feeding deterrents (Lin et al, 2020; Onkokesung et al, 2014; Onyilagha et al, 2012; Sharma & Sohal, 2013; Wang, Yu, et al, 2020). As indole primes these signalling components and metabolites, and as Ca 2+ and JA inhibition results in the disappearance of the indole‐dependent increase in defence and resistance, we propose that indole enhances tea resistance by enhancing early defence signalling, JA biosynthesis and defensive metabolite accumulation.…”

“…A number of desirable traits of this cultivar are characterized (Wang et al, 2020). The tea plants were maintained in plastic pots (15 cm depth and 14 cm diameter) with commercial potting soil, and grown in the greenhouse with regular fertilizer and water management as described previously (Lin et al, 2020). Two‐year‐old healthy tea plants with uniform height and width (28 cm height and 25 cm width) were selected and transferred to a controlled environment chamber (26 ± 2°C, 70–80% relative humidity, 12:12 hr light/dark) 3 days before the start of the experiments.…”

“…To evaluate the influence of indole exposure on defence metabolites, tea leaves were harvested at 0, 24 and 48 hr after the start of OS elicitation ( n = 5). Phenolamides and flavonoids were extracted with 80% ethanol, and then quantified by an UHPLC system (HClass, Waters, Manchester, UK) coupled to a triple quadrupole mass spectrometer (TQS‐Micro, Waters, Manchester, UK) as described previously (Lin et al, 2020; Wang et al, 2020). Phenolamides and flavonoid standards were purchased from Hangzhou Chemipanda Bio‐Tech Co., Ltd. (Hangzhou, China) and BioBioPha Biotech Company (Kunming, China).…”

Genome-Wide Identification of the Tify Gene Family and Their Expression Profiles in Response to Biotic and Abiotic Stresses in Tea Plants (Camellia sinensis)

“…Continuing research has demonstrated that the members of the TIFY gene family, especially members of the JAZ subfamily, play multiple roles in different plant developmental processes and the process of defense against biotic and abiotic stresses [1,8,10,11,13,31]. As evergreen plants, tea plants are frequently challenged by abiotic and biotic stresses, but information on the TIFY gene family is lacking, which hampers the research investigating resistance mechanisms [27,28,31]. The chromosome-level genomic sequence of the tea plant has been recently released, and the extensive annotated information provided in the tea genome provides fundamental material for comprehensive analysis of the CsTIFY family [32].…”

“…The tea plant Camellia sinensis (L.) O. Kuntze is an economically valuable woody plant, and this evergreen crop is continuously challenged by a wide variety of biotic stresses, such as the leaf-feeding pest Ectropis obliqua and the dominant leaf fungi bacterial Colletotrichum camelliae [27][28][29]. Previous studies based on transcriptomic strategies indicated that JAZ subfamily genes were involved in the interactions between the tea plant and biotic stresses [30].…”