GreenUPorto - Research Centre for Sustainable Agrifood Production & DGAOT, Faculty of Sciences of University of Porto, Rua da Agrária 747, 4485-646, Vairão, Portugal; Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005, Porto, Portugal.
Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005, Porto, Portugal.
Plant Physiol Biochem. 2021 May;162:258-266. doi: 10.1016/j.plaphy.2021.02.045. Epub 2021 Mar 3.
The use of plant elicitors for controlling Pseudomonas syringae pv. actinidiae (Psa), the etiological agent of the kiwifruit bacterial canker (KBC), has been analysed in the past and, while salicylic acid (SA) seems to decrease disease susceptibility, methyl jasmonate (MJ) shows an opposite effect. However, the metabolic and genomic responses of Psa-infected plants following elicitation with these two compounds, as compared with non-elicited Psa-inoculated plants, are poorly understood, being the focus of this study. Micropropagated A. chinensis 'Hayward' plants were elicited with MJ or SA, and further inoculated with Psa. Fifteen days post-inoculation, Psa population in MJ-treated plants was increased by 7.4-fold, whereas SA elicitation led to decreased Psa colonization (0.5-fold), as compared with non-elicited inoculated plants. Additionally, elicitation with MJ or SA generally decreased polyphenols and lignin concentrations (by at least 20%) and increased total proteins (by at least 50%). MJ led to the upregulation of SOD, involved in plant antioxidant system, and reporter genes for the jasmonic acid (JA) (JIH and LOX1), abscisic acid (SnRK), SA (ICS1), and ethylene (ACAS1, ETR1 and SAM) pathways. Moreover, it increased ABA (40%) and decreased carotenoids (30%) concentrations. Contrastingly, comparing with non-elicited Psa-inoculated plants, SA application resulted in the downregulation of antioxidant system-related genes (SOD and APX) and of reporter genes for ethylene (ETR1) and JA (JIH and ETR1). This study contributes to the understanding of potential mechanisms involved in kiwifruit plant defences against Psa, highlighting the role of the JA, ABA and ethylene in plant susceptibility to the pathogen.
过去曾分析过利用植物激发子来控制猕猴桃溃疡病菌（Psa），该病菌是猕猴桃细菌性溃疡病（KBC）的病原体。虽然水杨酸（SA）似乎降低了植物对病害的易感性，但茉莉酸甲酯（MJ）则表现出相反的效果。然而，与未处理的 Psa 接种植物相比，用这两种化合物处理后感染 Psa 的植物的代谢和基因组反应，是本研究的重点。用 MJ 或 SA 处理微繁殖的中华猕猴桃‘海沃德’植株，然后用 Psa 进一步接种。接种后 15 天，MJ 处理的植物中 Psa 的种群增加了 7.4 倍，而 SA 激发导致 Psa 定植减少（减少 0.5 倍），与未处理的接种植物相比。此外，用 MJ 或 SA 处理通常会降低多酚和木质素浓度（至少 20%），并增加总蛋白浓度（至少 50%）。MJ 导致参与植物抗氧化系统的 SOD 以及茉莉酸（JA）（JIH 和 LOX1）、脱落酸（SnRK）、SA（ICS1）和乙烯（ACAS1、ETR1 和 SAM）途径的报告基因上调。此外，它增加了 ABA（40%）并降低了类胡萝卜素（30%）浓度。相比之下，与未处理的 Psa 接种植物相比，SA 处理导致与抗氧化系统相关的基因（SOD 和 APX）以及乙烯（ETR1）和 JA（JIH 和 ETR1）报告基因下调。本研究有助于了解猕猴桃植物对 Psa 防御的潜在机制，突出了 JA、ABA 和乙烯在植物对病原体易感性中的作用。
