Sustainable Agricultural Systems Laboratory, USDA-ARS, Henry A. Wallace Beltsville Agricultural Research Center, Beltsville, MD, 20705-2350, USA; Center of Plant Biology, Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN, USA; Department of Natural Sciences, College of Arts and Sciences, Bowie State University, 14000 Jericho Park Rd., Bowie, MD, 20715, USA.
Statistics and Bioinformatics Group-Northeast Area, USDA-ARS, Henry A. Wallace Beltsville Agricultural Research Center, Beltsville, MD, 20705-2350, USA.
J Plant Physiol. 2024 Dec;303:154374. doi: 10.1016/j.jplph.2024.154374. Epub 2024 Nov 2.
Genetic improvements of solanaceous crops for quality and stress responsive traits are needed because of the central role vegetables and fruits have in providing nutrients to human diets. Copper amine oxidase (CuAO) encoding genes involved in metabolism of primary/di-amine nitrogenous compounds, play a role in balancing internal nitrogen (N) pools especially when external N supply fluctuates during growth, development and environmental stresses. In the present study, we investigated the occurrence, molecular evolution and possible role(s) of these unknown genes in tomato crops. Multiple genome-wide bioinformatics approaches led to the identification of eight bona fide CuAO genes (SlCuAO1-SlCuAO8) in the tomato genome with gene numbers like those in Arabidopsis and rice indicating their conserved functional relevance with a tandemly duplicated SlCuAO6-SlCuAO7 pair at chr.9. A conserved intron-exon size and phase distribution for SlCuAO2, 3, 4 pairs are similar to a recently identified single duckweed SpCuAO1 orthologue gene indicating its evolutionary conservation. Synteny analysis showed their closest association to Arabidopsis and but not with rice. Transcriptome data indicated that gene expression for about six genes (SlCuAO1, 2, 3, 4, 6, 7) is root specific, fruit specific for SlCuAO5 and flower specific for SlCuAO8 thus indicating amine oxidation is variable across tissues with a prominance in the root tissue. The majority of CuAO genes are negatively regulated by methyl jasmonate. Positive regulation, however, involves CuAO3/8. Transcript analysis of the ethylene-deficient transgenic lines indicated that ethylene is required for activation of SlCuAO4. CuAO4 and CuAO5 exhibited most significant tissues-independent gene expression responses across various nitrogen regimes. Drought, heat and N stress identified CuAO5 as an overlapping highly expressed gene that corroborates with putrescine accumulation for free and conjugated forms with an opposite abundance of bound forms. Taken together our study highlights new insights into the roles of copper amine oxidation genes and identifies CuAO5 as a multiple stress induced gene that can be used in genetic improvement programs for combining heat, drought and nitrogen use efficiency related traits.
需要对茄科作物进行遗传改良，以改善其品质和应对胁迫的特性，因为蔬菜和水果在为人类饮食提供营养方面起着核心作用。参与初级/二胺含氮化合物代谢的铜胺氧化酶（CuAO）编码基因在平衡内部氮（N）库方面发挥作用，特别是在生长、发育和环境胁迫期间外部 N 供应波动时。在本研究中，我们研究了这些未知基因在番茄作物中的发生、分子进化和可能的作用。多种全基因组生物信息学方法导致在番茄基因组中鉴定出 8 个真正的 CuAO 基因（SlCuAO1-SlCuAO8），其基因数量与拟南芥和水稻相似，表明它们具有保守的功能相关性，在 chr.9 上有一个串联重复的 SlCuAO6-SlCuAO7 对。SlCuAO2、3、4 对的保守内含子-外显子大小和相位分布与最近鉴定的单个浮萍 SpCuAO1 直系同源基因相似，表明其进化保守性。共线性分析表明，它们与拟南芥的关系最密切，而与水稻的关系不密切。转录组数据分析表明，大约 6 个基因（SlCuAO1、2、3、4、6、7）的基因表达是根特异性的，SlCuAO5 是果实特异性的，SlCuAO8 是花特异性的，因此表明胺氧化是可变的，以根组织为主。大多数 CuAO 基因受茉莉酸甲酯的负调控。然而，正调控涉及 CuAO3/8。乙烯缺陷型转基因系的转录分析表明，乙烯是激活 SlCuAO4 所必需的。SlCuAO4 和 CuAO5 在各种氮条件下表现出最显著的组织独立基因表达响应。干旱、热和氮胁迫确定 CuAO5 是一个高度表达的重叠基因，与腐胺积累的游离和共轭形式相对应，结合结合形式的丰度相反。总之，我们的研究强调了铜胺氧化基因的作用的新见解，并确定 CuAO5 是一个多胁迫诱导基因，可以用于遗传改良计划，以结合耐热、耐旱和氮利用效率相关特性。
