低温胁迫下2种倍性滇山茶生理生化变化及抗氧化酶活性相关基因表达分析

Physiological and biochemical changes and gene expression related to antioxidant enzyme activity of two ploidy Camellia reticulata species under low temperature stress

【目的】滇山茶为云南八大名花之首,其耐寒性较差,从生理与分子层面探讨2种倍性滇山茶的耐寒性,可为滇山茶耐寒基因挖掘及分子育种提供参考。【方法】以野生滇山茶四倍体(4X)和六倍体(6X)的1年生幼苗为材料,测定低温(-4℃)胁迫处理后的滇山茶叶片生理指标及转录组测序。【结果】从叶片表型观测看,在胁迫期至复温期中,六倍体叶片受损程度相对较小,抗寒表现优于四倍体;从生理指标结果看,除MDA及GSH外,六倍体的其他生理指标含量积累均大于四倍体;将抗氧化酶活性与其差异基因进行相关性分析发现,在四倍体和六倍体中,与GSH含量及POD活性呈显著相关性的基因分别为5个和7个、7个和17个,仅六倍体有2个基因与SOD活性显著相关。【结论】六倍体较四倍体能更有效抵御植株遭受的低温胁迫伤害;抗氧化酶相关基因可能通过调控其活性参与对低温的响应。

[Objective]Camellia reticulata is the first of the eight famous flowers in Yunnan,but it is poor in cold tolerance.This paper discusses the cold tolerance of two ploidy C.reticulata from the physiological and molecular levels,which can provide references for the mining of cold tolerance genes and molecular breeding of C.reticulata.[Methods]Using tetraploid(4X)and hexaploid(6X)annual seedlings of wild C.reticulata as materials,physiological indexes and transcriptomic sequencing of leaves of C.reticulata were analyzed after low temperature(-4℃)treatment.[Results]Based on the observation of leaf pheno-type,from the stress period to the rewarming period,the damage degree of the hexaploid leaves was rela-tively smaller,and the cold resistance performance of the hexaploid leaves was better than that of the tetraploid leaves.According to the results of physiological indexes,except for MDA and GSH,the accu-mulation of other physiological indexes of the hexaploid was greater than that of the tetraploid.Correlation analysis of antioxidase activity and the differential genes showed that 5 and 7,7 and 17 genes were signifi-cantly correlated with GSH content and POD activity in tetraploid and hexaploid,respectively,and only 2 genes in hexaploid were significantly correlated with SOD activity.[Conclusion]Hexaploid is more effec-tive than tetraploid in alleviating the damage of plants under low temperature stress.Antioxidase-related genes may be involved in the regulation of low temperature resistance by regulating their activity.