苹果B型细胞分裂素响应因子MdARR11对干旱胁迫的抗性分析

Resistance Analysis of Apple Type-B Cytokinin Response Factor MdARR11 to Drought Stress

B型反应调节因子(ARRs)作为细胞分裂素的正响应因子在植物生长发育中发挥重要作用。为探究ARR11在应对苹果干旱胁迫过程中的功能,本研究以嘎拉3苹果(Malus domestica Borkh.cv.Gala 3)为试验材料,利用聚合酶链式反应(PCR)扩增技术,获得了B型细胞分裂素响应因子MdARR11。该序列全长2248 bp,编码613个氨基酸,包含type-B-REC结构域,C端含有一个MYB-like的DNA结合域。组织特异性表达分析显示该基因在茎中表达量最高。实时荧光定量PCR(qRT-PCR)分析结果表明,干旱胁迫抑制MdARR11的表达。为进一步研究MdARR11在干旱胁迫中的功能,获得了过表达MdARR11苹果愈伤组织。使用6%聚乙二醇6000(PEG6000)模拟干旱处理野生型及过表达愈伤组织,观察愈伤组织生长速率、大小并检测鲜重、相对电导率、丙二醛(MDA)、脯氨酸(Pro)、可溶性蛋白积累量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性。结果表明,过表达MdARR11提高了愈伤组织细胞膜的脂膜过氧化程度、降低了渗透调节物质的积累及抗氧化酶活性。综上所述,MdARR11降低了苹果愈伤组织对干旱胁迫的耐受性。本研究为进一步探索MdARR11基因的生物学功能及作用机理奠定了基础。

B-type ARRs play an important role as positive response factors for cytokinins in plant growth and development.In order to explore the function of ARR11 in response to drought stress in apple,in this study Gala 3 apple(Malus domestica Borkh.cv Gala 3)was used as the test material and the B type cytokinin response factor gene MdARR11 was obtained using PCR amplification technology.The sequence was 2248 bp in length and encodes 613 amino acids.It contains a type-B REC domain and a MYB like DNA binding domain at the C-terminus.Tissue-specific expression analysis showed that the gene had the highest expression level in the stem.The results of quantitative real-time PCR(qRT-PCR)analysis showed that drought stress inhibited the expression of MdARR11.To further validate the function of MdARR11 under drought stress,MdARR11-overexpressed apple calli was obtained.Wild type and overexpression of calli were treated with 6%,PEG6000 to simulate drought stress,the growth rate,size,and fresh weight,relative conductivity,the malondialdehyde(MDA)and proline(Pro),the accumulation of soluble protein and superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)activity in calli were analyzed.The results showed that overexpression of MdARR11 increased the degree of lipid membrane peroxidation in callus cell membranes,decreased the accumulation of osmoregulation substances,and reduced antioxidant enzyme activity.In summary,MdARR11 reduced the tolerance of apple callus to drought stress.This study lays a foundation for further exploring the biological function and mechanism of action of the MdARR11 gene.