Mulberry is a fast growing economically important tree for sericulture industry and contains compounds for preventing and treating several diseases and ailments. The quality and quantity of mulberry leaf available to produce silk fibre and for medicinal purpose is greatly affected by number of foliar diseases, out of which powdery mildew is the major one. Imparting genetic resistance becomes an important approach in disease management in mulberry as spraying of fungicides has harmful effects on silkworm growth and development. Deployment of non-functional susceptible genes such as Mildew resistance Locus O (MLO) against powdery mildew in few crops stimulated to identify and characterize MLO genes in mulberry. In this study, genome wide analysis identified 16 MLO genes in Morus notabilis. Phylogenetic analysis found that MnMLO2, MnMLO6A, MnMLO6B, MnMLO12A and MnMLO12B clustered with functionally characterized MLOs associated with powdery mildew susceptibility in dicot species. Gene expression analysis indicated increased transcript abundance of MnMLO2, MnMLO6A, and MnMLO12A in response to powdery mildew infection. Further, conserved motifs exclusive to functionally characterized MLOs were identified in MnMLO1C, MnMLO2 and MnMLO6A proteins. Combined analysis of the phylogenetic relationship, conserved motif analysis and gene expression in response to infection identified MnMLO2 and MnMLO6A as potential candidate genes involved in powdery mildew susceptibility in mulberry. Identification and deployment of natural and induced mutations in the candidate genes can be useful for mulberry breeding programs to develop powdery mildew resistant varieties.

中文翻译：

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全基因组表征表明，MnMLO2和MnMLO6A是参与桑树白粉病敏感性的候选基因。

桑树是用于蚕桑业的经济增长迅速的重要树种，并且包含用于预防和治疗多种疾病的化合物。可用于生产丝纤维和用于医学目的的桑叶的质量和数量在很大程度上受叶病的影响，其中以白粉病为主要病害。由于喷洒杀真菌剂会对蚕的生长和发育产生有害影响，因此提高遗传抗性成为桑树疾病管理的重要途径。在少数受到刺激以鉴定和表征桑树中MLO基因的农作物中，部署了非功能性易感基因，例如抗白粉病的霉病抗性座位O（MLO）。在这项研究中，全基因组分析确定了桑属中的16个MLO基因。系统发育分析发现，MnMLO2，MnMLO6A，MnMLO6B，MnMLO12A和MnMLO12B与功能性特征的MLO聚集在一起，与双子叶植物的白粉病易感性相关。基因表达分析表明，响应白粉病感染，MnMLO2，MnMLO6A和MnMLO12A的转录丰度增加。此外，在MnMLO1C，MnMLO2和MnMLO6A蛋白中鉴定了功能性MLO专有的保守基序。系统发育关系的综合分析，保守的基序分析和响应感染的基因表达确定MnMLO2和MnMLO6A为桑树白粉病易感性的潜在候选基因。候选基因中自然突变和诱导突变的鉴定和部署可用于桑树育种计划，以开发抗白粉病品种。