Abstract:

【Objective】 Clarifying the response characteristics of rice cysteine-rich receptor-like kinases (CRKs) family genes to Rhizoctonia solani and plant hormones is important preliminary work to analyze the functions of CRKs in rice resistance to R. solani. 【Method】 A phylogenetic tree of 45 CRKs in rice was constructed by bioinformatics. qPCR was used to analyze their response characteristics to R. solani, plant hormones ethylene (ET), jasmonic acid (JA), salicylic acid (SA) and cytokinin (CK), and their expression patterns in different tissues.【Result】 The rice CRKs family can be divided into four groups. Most of the CRKs clustered or closely distributed on chromosomes from the same group or branch. Forty-one CRKs responded to R. solani infection, and 17 of them responded strongly. Combined with their tissue expression patterns, it was found that 10 of the 17 CRKs, including CRK15, CRK23, CRK24, CRK26, CRK27, CRK28, CRK29, CRK30, CRK31 and CRK33, were expressed strongly in leaf sheathes and leaves, suggesting that these genes may be involved in regulating resistance to sheath blight. Most of CRKs from the same branch had similar response characteristics to R. solani, indicating that these CRKs may have functional redundancy in regulating resistance to R. solani. Forty CRKs responded to three or four kinds of plant hormones, and their responses to different hormones varied, indicating that CRKs might be widely involved in these plant hormones-mediated defense pathways. There were 17 CRKs with opposite responses to JA and SA, 21 with similar responses to JA and SA, 21 with similar responses to ET and JA, and 23 with similar responses to ET and SA, respectively. These genes may be involved in the interactions among ET, JA and SA. The results not only reflected the synergistic and antagonistic effects of ET, JA and SA signaling pathways, but also indicated that these genes may participate in the interactions among ET, JA and SA.【Conclusion】 Some rice CRKs involved in the regulation of rice sheath blight resistance have been identified, and they may play roles in the plant hormones-mediated defense pathways, which provides scientific clues for us to further explore the function of CRKs in regulating rice sheath blight resistance.

Key words: rice, OsCRK gene, sheath blight, defense-related hormone, response characteristics

摘要：

【目的】明确水稻富含半胱氨酸类受体激酶（Cysteine-rich receptor-like kinases,CRK）家族基因对纹枯病菌侵染和植物激素的响应特征,是解析CRK在水稻纹枯病抗性中的功能的重要前期工作。【方法】利用生物信息学方法构建了水稻45个CRK的系统发育树,并利用qPCR分析了它们对纹枯病菌和对植物激素乙烯（Ethylene,ET）、茉莉酸（Jasmonic acid,JA）、水杨酸（Salicylic acid,SA）和细胞分裂素（Cytokinin,CK）等的响应特征,以及在水稻不同组织中的表达模式。【结果】水稻CRK家族可分为4个组,在染色体上成簇或紧密分布的CRK大部分来自同一组或同一分支。41个CRK响应纹枯病菌侵染,其中17个响应强烈;结合组织表达模式,发现这17个CRK基因中,CRK15、CRK23、CRK24、CRK26、CRK27、CRK28、CRK29、CRK30、CRK31和CRK33等10个基因在叶鞘和叶片中表达较强,暗示这些基因可能参与了对纹枯病的抗性;大部分同一分支的两个同源性较高的CRK对纹枯病菌的响应特征类似, 表明这些CRK基因在调控纹枯病抗性上可能存在功能冗余。40个CRK对3种或4种植物激素均有响应,它们对不同激素的响应存在差异性,说明CRK可能广泛参与这些激素介导的防御信号途径;对JA和SA响应相反的有17个,对JA和SA、ET和JA、ET和SA响应类似的分别有21、21、23个。这不仅反映了ET、JA、SA信号途径间的协同和拮抗作用,也说明这些基因可能参与ET、JA和SA间的交互作用。【结论】鉴定到一些可能参与调控水稻纹枯病抗性的CRK基因,且它们可能在植物激素介导的防御途径中起作用。这为我们进一步探索CRK在调控水稻纹枯病抗性上的功能提供了科学线索。

关键词: 水稻, OsCRK基因, 纹枯病, 防御相关激素, 响应特征