Institute of Plant Sciences, Agricultural Research Organization, The Volcani Center, 68 HaMaccabim Road, P.O. Box 15159, Rishon LeZion, 7505101, Israel.
The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot, 76100, Israel.
Plant Mol Biol. 2017 Jul;94(4-5):481-494. doi: 10.1007/s11103-017-0619-3. Epub 2017 May 23.
Newly identified genes that are preferentially expressed in potato skin include genes that are associated with the secondary cell wall and stress-related activities and contribute to the skin's protective function. Microarrays were used to compare the skin and tuber-flesh transcriptomes of potato, to identify genes that contribute to the unique characteristics of the skin as a protective tissue. Functional gene analysis indicated that genes involved in developmental processes such as cell division, cell differentiation, morphogenesis and secondary cell wall formation (lignification and suberization), and stress-related activities, are more highly expressed in the skin than in the tuber flesh. Several genes that were differentially expressed in the skin (as verified by qPCR) and had not been previously identified in potato were selected for further analysis. These included the StKCS20-like, StFAR3, StCYP86A22 and StPOD72-like genes, whose sequences suggest that they may be closely related to known suberin-related genes; the StHAP3 transcription factor that directs meristem-specific expression; and the StCASP1B2-like and StCASP1-like genes, which are two orthologs of a protein family that mediates the formation of Casparian strips in the suberized endodermis of Arabidopsis roots. An examination of microtubers induced from transgenic plants carrying GUS reporter constructs of these genes indicated that these genes were expressed in the skin, with little to no expression in the tuber flesh. Some of the reporter constructs were preferentially expressed in the inner layers of the skin, the root endodermis, the vascular cambium and the epidermis of the stem. Cis-regulatory elements within the respective promoter sequences support this gene-expression pattern.
新鉴定的在马铃薯皮中优先表达的基因包括与次生细胞壁和应激相关活动相关的基因，这些基因有助于皮肤的保护功能。利用微阵列比较了马铃薯皮和块茎肉的转录组，以鉴定有助于皮肤作为保护组织的独特特征的基因。功能基因分析表明，参与细胞分裂、细胞分化、形态发生和次生细胞壁形成（木质化和栓质化）以及应激相关活动等发育过程的基因在皮中比在块茎肉中表达更高。一些在皮中差异表达的基因（通过 qPCR 验证）在马铃薯中尚未被鉴定，被选择进行进一步分析。这些基因包括 StKCS20 样、StFAR3、StCYP86A22 和 StPOD72 样基因，它们的序列表明它们可能与已知的栓质相关基因密切相关；StHAP3 转录因子，指导分生组织特异性表达；以及 StCASP1B2 样和 StCASP1 样基因，它们是介导拟南芥根栓内层 Casparian 带形成的蛋白家族的两个同源基因。对携带这些基因的 GUS 报告基因构建体的转基因植株诱导的微型块茎进行检查表明，这些基因在皮中表达，在块茎肉中几乎不表达。一些报告基因构建体在皮的内层、根内皮层、维管形成层和茎的表皮中优先表达。各自启动子序列中的顺式调控元件支持这种基因表达模式。
