Shoaib Muhammad, Yang Wenlong, Shan Qiangqiang, Sajjad Muhammad, Zhang Aimin
The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
University of Chinese Academy of Sciences, Beijing, China.
PeerJ. 2019 Jan 31;7:e6300. doi: 10.7717/peerj.6300. eCollection 2019.
Cytokinins (CKs) are involved in determining the final grain yield in wheat. Multiple gene families are responsible for the controlled production of CKs in plants, including isopentenyl transferases for synthesis, zeatin O-glucosyltransferases for reversible inactivation, β-glucosidases for reactivation, and CK oxidases/dehydrogenases for permanent degradation. Identifying and characterizing the genes of these families is an important step in furthering our understanding of CK metabolism. Using bioinformatics tools, we identified four new , four new , and 25 new genes in common wheat. All of the genes harbored the characteristic conserved domains of their respective gene families. We renamed genes on the basis of their true orthologs in rice and maize to remove inconsistencies in the nomenclature. Phylogenetic analysis revealed the early divergence of monocots from dicots, and the gene duplication event after speciation was obvious. Abscisic acid-, auxin-, salicylic acid-, sulfur-, drought- and light-responsive -regulatory elements were common to most of the genes under investigation. Expression profiling of CK metabolic gene families was carried out at the seedlings stage in AA genome donor of common wheat. Exogenous application of phytohormones (6-benzylaminopurine, salicylic acid, indole-3-acetic acid, gibberellic acid, and abscisic acid) for 3 h significantly upregulated the transcript levels of all four gene families, suggesting that plants tend to maintain CK stability. A 6-benzylaminopurine-specific maximum fold-change was observed for and in root and shoot tissues, respectively; however, the highest expression level was observed in the gene family, indicating that the reactivation of the dormant CK isoform is the quickest way to counter external stress. The identification of new CK metabolic genes provides the foundation for their in-depth functional characterization and for elucidating their association with grain yield.
细胞分裂素（CKs）参与决定小麦的最终籽粒产量。多个基因家族负责植物中CKs的可控合成，包括用于合成的异戊烯基转移酶、用于可逆失活的玉米素O - 葡萄糖基转移酶、用于再激活的β - 葡萄糖苷酶以及用于永久降解的CK氧化酶/脱氢酶。鉴定和表征这些家族的基因是深化我们对CK代谢理解的重要一步。利用生物信息学工具，我们在普通小麦中鉴定出4个新的[具体基因类型1]、4个新的[具体基因类型2]和25个新的[具体基因类型3]基因。所有这些基因都含有各自基因家族的特征性保守结构域。我们根据它们在水稻和玉米中的直系同源基因对[相关基因]进行了重命名，以消除命名上的不一致。系统发育分析揭示了单子叶植物与双子叶植物的早期分化，物种形成后的基因复制事件很明显。脱落酸、生长素、水杨酸、硫、干旱和光响应的[相关基因]调控元件在大多数被研究基因中很常见。在普通小麦A基因组供体的幼苗期对CK代谢基因家族进行了表达谱分析。外源施加植物激素（6 - 苄基腺嘌呤、水杨酸、吲哚 - 3 - 乙酸、赤霉素和脱落酸）3小时显著上调了所有四个基因家族的转录水平，表明植物倾向于维持CK的稳定性。在根和茎组织中分别观察到[具体基因类型1]和[具体基因类型2]对6 - 苄基腺嘌呤有特异性的最大倍数变化；然而，在[具体基因类型3]基因家族中观察到最高的表达水平，表明休眠CK异构体的再激活是应对外部胁迫的最快方式。新CK代谢基因的鉴定为深入进行其功能表征以及阐明它们与籽粒产量的关联奠定了基础。
