No abstract

The TIFY family is a plant-specific gene family that is involved in regulating a variety of plant processes, including developmental and defense responses. The chromosome-level genome of the tea plant (Camellia sinensis) has recently been released, but a comprehensive view of the TIFY family in C. sinensis (the CsTIFY genes) is lacking. The current study performed an extensive genome-wide identification of CsTIFY genes. The phylogenetics, chromosome location, exon/intron structure, and conserved domains of these genes were analyzed to characterize the members of the CsTIFY family. The expression profiles of the CsTIFY genes in four organs were analyzed, and they showed different spatial expression patterns. All CsJAZ genes were observed to be induced by jasmonate acid (JA) and exhibited different responses to abiotic and biotic stresses. Six of seven CsJAZ genes (CsJAZ1, CsJAZ2, CsJAZ3, CsJAZ4, CsJAZ7, and CsJAZ8) were upregulated by mechanical wounding and infestation with the tea geometrid (Ectropis obliqua), while infection with tea anthracnose (Colletotrichum camelliae) primarily upregulated the expression levels of CsJAZ1 and CsJAZ10. In addition, CsJAZs were observed to interact with CsMYC2 and AtMYC2. Therefore, the results of this study may contribute to the functional characterization of the CsTIFY genes, especially the members of the JAZ subfamily, as regulators of the JA-mediated defense response in tea plant.

The tea plant, Camellia sinensis (L.) O. Kuntze, is an economically important, perennial woody plant rich in catechins. Although catechins have been reported to play an important role in plant defences against microbes, their roles in the defence of tea plants against herbivores remain unknown. In this study, we allowed the larvae of Ectropis grisescens, a leaf‐feeding pest, to feed on the plants, and alternatively, we wounded the plants and then treated them with E. grisescens oral secretions (WOS). Both approaches triggered jasmonic acid‐, ethylene‐ and auxin‐mediated signalling pathways; as a result, plants accumulated three catechin compounds: (+)‐catechin, epicatechin and epigallocatechin. Not only was the mass of E. grisescens larvae fed on plants previously infested with E. grisescens or treated with WOS significantly lower than that of larvae fed on controls, but also artificial diet supplemented with epicatechin, (+)‐catechin or epigallocatechin gallate reduced larval growth rates. In addition, the exogenous application of jasmonic acid, ethylene or auxin induced the biosynthesis of the three catechins, which, in turn, enhanced the resistance of tea plants to E. grisescens, leading to the coordination of the three signalling pathways. Our results suggest that the three catechins play an important role in the defences of tea plants against E. grisescens.