Kiekens Raphaël, de Koning Ramon, Toili Mary Esther Muyoka, Angenon Geert
Research Group Plant Genetics, Vrije Universiteit Brussel, 1050 Brussels, Belgium.
Department of Horticulture and Food Security, School of Agriculture and Environmental Sciences, College of Agriculture and Natural Resources, Jomo Kenyatta University of Agriculture and Technology, Nairobi P.O. Box 62000-00200, Kenya.
Plants (Basel). 2022 Jul 1;11(13):1762. doi: 10.3390/plants11131762.
DHDPS is a key enzyme in the aspartate-derived lysine biosynthesis pathway and an evident object of study for biofortification strategies in plants. DHDPS isoforms with novel regulatory properties in were demonstrated earlier and hypothesized to be involved in abiotic and biotic stress responses. Here, we present a phylogenetic analysis of the gene family in land plants which establishes the existence of a legume-specific class of DHDPS, termed DHDPS B-type, distinguishable from the DHDPS A-type commonly present in all land plants. The genome comprises two A-type genes (; , ; ) and one B-type (; ). To further investigate the expression pattern of the DHDPS isozymes in different plant tissues and under various stress conditions, 461 RNA-seq experiments were exploited and re-analyzed covering two expression atlases, 13 abiotic and 5 biotic stress studies. is seen almost exclusively expressed in roots and nodules in addition to old cotyledons or senescent leaves while both A-types are expressed constitutively in all tissues analyzed with the highest expression in mature seeds. Furthermore, expression is significantly upregulated in some but not all stress responses including salt stress, flooding, ethylene or infection with and coincides with downregulation of A-types. In conclusion, we demonstrate the potential of an in-depth RNA-seq re-analysis for the guidance of future experiments and to expand on current knowledge.
二氢吡啶二羧酸合酶（DHDPS）是天冬氨酸衍生的赖氨酸生物合成途径中的关键酶，也是植物生物强化策略的一个明显研究对象。此前已证明了具有新调控特性的DHDPS同工型，并推测其参与非生物和生物胁迫反应。在这里，我们对陆地植物中的该基因家族进行了系统发育分析，确定了存在一类豆科植物特有的DHDPS，称为DHDPS B型，与所有陆地植物中普遍存在的DHDPS A型不同。该基因组包含两个A型DHDPS基因（; ，; ）和一个B型基因（; ）。为了进一步研究DHDPS同工酶在不同植物组织和各种胁迫条件下的表达模式，我们利用并重新分析了461个RNA测序实验，这些实验涵盖了两个表达图谱、13项非生物胁迫研究和5项生物胁迫研究。除了老的子叶或衰老的叶子外，几乎只在根和根瘤中观察到B型基因的表达，而两种A型基因在所有分析的组织中组成型表达，在成熟种子中表达最高。此外，B型基因的表达在一些但不是所有的胁迫反应中显著上调，包括盐胁迫、水淹、乙烯或感染，并且与A型基因的下调同时发生。总之，我们证明了深入的RNA测序重新分析在指导未来实验和扩展现有知识方面的潜力。
