钙对枳生长发育及柑橘溃疡病抗性的影响  

Effects of Calcium on Growth and Development of Poncirus trifoliata and Resistance to Citrus Canker

作　　者：肖桂华 文康 韩健[4] 郝晨星[1,2,3] 叶蓉春 朱亦赤 萧顺元[1] 邓子牛 马先锋 XIAO GuiHua;WEN Kang;HAN Jian;HAO ChenXing;YE RongChun;ZHU YiChi;XIAO ShunYuan;DENG ZiNiu;MA XianFeng(College of Horticulture,Hunan Agricultural University,Changsha 410128;Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding,Ministry of Education,Changsha 410128;National Center for Citrus Improvement(Changsha),Changsha 410128;Hunan Institute of Horticulture,Changsha 410125)

机构地区：[1]湖南农业大学园艺学院,长沙410128 [2]园艺作物种质创新与新品种选育教育部工程研究中心,长沙410128 [3]国家柑橘改良中心长沙分中心,长沙410128 [4]湖南省园艺研究所,长沙410125

出　　处：《中国农业科学》2022年第19期3767-3778,共12页Scientia Agricultura Sinica

基　　金：国家重点研发计划(2018YFD1000300);湖湘高层次人才聚集工程(2019RS1052)。

摘　　要：【背景】柑橘溃疡病是由柑橘黄单胞杆菌柑橘致病变种(Xanthomonas citri subsp.citri,Xcc)引起的细菌性病害,可侵染枝、叶、果,危害几乎所有的柑橘主栽品种。前期对湖南省39个柑橘园的调查结果显示柑橘果园土壤酸化和交换性钙缺乏严重,叶片中均存在钙缺乏现象。钙是植物所需大量元素之一,钙缺乏会造成植物营养失衡,生长势下降,植物免疫水平受影响。然而,钙元素对柑橘溃疡病抗性的影响尚不明确。【目的】分析对柑橘溃疡病敏感的枳(Poncirus trifoliata)在不同钙浓度处理下叶片注射接种Xcc后的致病差异,探讨钙在Xcc侵染枳叶片过程中的作用。【方法】采用沙培法对枳实生苗进行0、0.75、3、30 mmol·L^(-1)钙浓度处理,分别测定枳生长期的生物量、叶绿素a和b浓度、根系和叶片钙元素含量、观察根系活性氧(ROS)的产生和胼胝质沉积,并分析枳叶片接种Xcc后细胞壁合成相关基因及免疫途径相关基因诱导表达变化特征。【结果】以3 mmol·L^(-1)钙处理为对照,0、0.75和30 mmol·L^(-1)钙处理后,枳地上部和地下部生长发育均受抑制,叶绿素a和b浓度降低;根系与叶片中的钙含量与外源钙施加量成正比;不同钙浓度处理后根系中产生ROS和胼胝质沉积,在3 mmol·L^(-1)处理时达到最大值;枳叶片接种Xcc后,随着钙浓度增加,叶片症状逐渐减轻,但Xcc的生长量无明显差异;相较于3 mmol·L^(-1)处理,参与细胞壁合成相关基因PtCESA4在0 mmol·L^(-1)处理下受Xcc诱导先上调表达后下调表达,在30 mmol·L^(-1)处理下受Xcc诱导上调表达,PtPME和PtFLA在0 mmol·L^(-1)处理下受Xcc诱导下调表达,在30 mmol·L^(-1)处理下受Xcc诱导上调表达;叶片接种Xcc 0、2、4、6 dpi后免疫途径相关基因PtGSL、PtGST1、PtWRKY22在30 mmol·L^(-1)处理下受Xcc诱导表达水平高于0和3 mmol·L^(-1)处理。【结论】钙缺乏和过量均会影响枳生长发育,引起叶片失绿,【Background】Citrus canker is a bacterial disease caused by Xanthomonas citri subsp.citri(Xcc),which can infect branches,leaves and fruits,and affects almost all major citrus varieties.The results of a previous survey of 39 citrus orchards in Hunan Province showed that soil acidification and exchange calcium deficiency in citrus orchards were serious and calcium deficiency existed in all leaves.Calcium is one of the elements required by plants in large quantities,and calcium deficiency causes nutritional imbalance,reduced growth potential and compromised plant immunity level.However,the effect of calcium element on the process of citrus infection with canker is not clear.【Objective】The objective of this study is to analyze the pathogenic differences after inoculation with Xcc in Poncirus trifoliata(sensitive to citrus canker)leaves under different calcium concentrations,and to explore the role of calcium in Xcc infection of P.trifoliata leaves.【Method】The seedlings of P.trifoliata were sand cultured with calcium concentrations of 0,0.75,3,and 30 mmol·L^(-1).During the growth period of P.trifoliata,the biomass,chlorophyll a and b concentrations,and calcium content in roots and leaves were determined,as well as the formation of reactive oxygen species(ROS)in roots and callose deposition.The effects of Xcc inoculation on cell wall synthesis-related genes and immune-related genes in P.trifoliata leaves were investigated.【Result】Compared with 3 mmol·L^(-1) calcium treatment,0,0.75 and 30 mmol·L^(-1) calcium treatments inhibited the growth and development of aboveground and underground parts of P.trifoliate,and chlorophyll a and b concentrations decreased.The calcium content in roots and leaves was proportional to the amount of exogenous calcium.ROS and callose deposition were generated in roots after treatment with different calcium concentrations,reaching the maximum at 3 mmol·L^(-1).After inoculation with Xcc,the leaf symptoms gradually decreased with the increase of calcium concentration,but the

关 键 词：柑橘溃疡病 柑橘黄单胞杆菌柑橘致病变种 钙 枳 免疫 

分 类 号：S436.66[农业科学—农业昆虫与害虫防治]