枣裂果生理特性与相关基因的表达分析

Physiological characteristics of Jujube fruit cracking and expression analysis of related genes

[目的]本文旨在了解果皮结构物质、植物内源激素、细胞壁代谢酶活性及相关基因与裂果的关系,揭示导致枣裂果的分子机制,为枣裂果防治提供理论依据。[方法]以易裂枣品种‘伏脆蜜’为试材,测定盛花后40~90 d,枣果果皮中结构物质纤维素、半纤维素、果胶、IAA、ABA和GA3含量,POD、纤维素酶、果胶酶活性,利用实时荧光定量PCR技术检测细胞壁代谢酶及激素相关基因在枣果生长发育不同阶段的表达。[结果]盛花期后70~90 d Endoglucanase12下调表达,Pectinesterase17上调表达。裂果期间纤维素酶活性下降了25.01%,裂果前后果胶酶活性变化较小;盛花后70~90 d,半纤维素含量降低44%,盛花后90 d纤维素、ISP及总果胶含量最高,分别是3.60%,2.19%,6.74%,裂果期WSP含量低于未裂果时期。盛花后70~90 d,POD活性剂POD4、POD17、POD51表达量快速降低;盛花后60~90d IAA及GA3含量分别下降了27.62%、21.73%,裂果前后IAA含量变化较小。裂果期ARF、JAZ、SAUR表达量快速下降,AUX/IAA和GH3.1表达量显著高于未裂果时期。[结论]Endoglucanase12、Pectinesterase17、POD4、POD17、POD51可通过调控纤维素酶、果胶酶、POD活性,影响细胞壁物质含量,降低细胞壁结构稳定性、延展性,导致裂果率上升;JAZ、SAUR、ARF、GH3.1、AUX/IAA可调控植物激素合成从而影响裂果。

[Objective]The study was designed to understand the relationship between peel structural substances,plant endogenous hormones,cell wall metabolic enzyme activities and related genes and fruit cracking,to reveal the molecular mechanism leading to the decline of peel ductility,and to provide theoretical basis for the prevention and treatment of fruit cracking.[Methods]The contents of cellulose,hemicellulose,pectin,IAA,ABA and GA3 and the activities of POD,cellulase and pectinase in the peel of easily split jujube’Fuzhongmi’were determined in 40 d to 90 d after fully blooming.Real-time quantitative PCR was used to detect the expression of cell wall metabolic enzymes and hormone-related genes at different stages of jujube fruit growth and development.[Results]Endoglucanase12 was down-regulated and Pectinesterase17 was up-regulated between70~90 d after flowering.During fruit cracking period,cellulase activity was decreased by 25.01%,while pectinase activity changed a little before and after fruit splitting.The hemicellulose content was decreased by 44%during 70~90 d after full flowering.The contents of cellulose,ISP and total pectin reached the highest values at 3.60%,2.19%and 6.74%,respectively in 90 d after full flowering.WSP content in cracking stage was lower than that in uncracking stage.During the period of 70~90 d after flowering,the expression levels of POD active agents POD4,POD17 and POD51 was inhibited greatly.The contents of IAA and GA3 were decreased by 27.62%and 21.73%from 60 d to 90 d after flowering,respectively.The expression levels of ARF,JAZ and SAUR were reduced rapidly at splitting stage,while the expression levels of AUX/IAA and GH3.1 were significantly higher than those at non-splitting stage.[Conclusion]Endoglucanase12,Pectinesterase17,POD4,POD17,and POD51 affected the content of cell wall substances by regulating the activities of cellulase,pectinase and POD,and reduced the stability and ductility of cell wall structure,leading to the increase of fruit cracking rate.JAZ,SAUR,ARF,GH3.1,AUX/IAA could regulate hormone synthesis and affected fruit cracking.