Su Liangchen, Liu Shuai, Liu Xing, Zhang Baihong, Li Meijuan, Zeng Lidan, Li Ling
Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, South China Normal University, Guangzhou, Guangdong, China.
Department of Bioengineering, Zunyi Medical University, Zhuhai, Guangdong, China.
PeerJ. 2021 Mar 16;9:e10976. doi: 10.7717/peerj.10976. eCollection 2021.
The peanut () is a crop plant of high economic importance, but the epigenetic regulation of its root growth and development has not received sufficient attention. Research on has shown that histone deacetylases (HDACs) are involved in cell growth, cell differentiation, and stress response. Few studies have focused on the role of HDACs in the root development of other plants, particularly crop plants. In earlier studies, we found large accumulations of histone deacetylase 1 () mRNA in peanut roots. However, we did not explore the role of AhHDA1 in peanut root development.
In this paper, we investigated the role of the peanut gene and focused on the effect of altered expression in hairy roots at both the phenotypic and transcriptional levels. We analyzed the transformation of hairy roots using Agrobacterium rhizogenes and RNA sequencing to identify differentially expressed genes that were assigned to specific metabolic pathways. Transgenic hairy roots were used as experimental material to analyze the downstream genes expression and histone acetylation levels. To thoroughly understand function, we also simultaneously screened the -interacting proteins using a yeast two-hybrid system.
-overexpressing hairy roots were growth-retarded after 20 d in vitro cultivation, and they had a greater accumulation of superoxide anions and hydrogen peroxide than the control and RNAi groups. overexpression in hairy roots accelerated flux through various secondary synthetic metabolic pathways, as well as inhibited the primary metabolism process. overexpression also caused a significant upregulation of genes encoding the critical enzyme chalcone synthase (, CHS) in the flavonoid biosynthesis pathway, hydroxyisoflavanone synthase () in the isoflavonoid biosynthesis pathway, and caffeoyl-CoA O-methyltransferase () in the phenylpropanoid biosynthesis pathway. In contrast, ferredoxin 1 (), the polypeptide of the oxygen-evolving complex of photosystem II (), and ribulose bisphosphate carboxylase () in the photosynthetic pathway were significantly downregulated by overexpression. The expression levels of these genes had a positive correlation with histone acetylation levels.
Our results revealed that the relationship between altered gene metabolism activities and overexpression was mainly reflected in flavonoid, isoflavonoid, and phenylpropanoid metabolism. overexpression retarded the growth of transgenic hairy roots and may be associated with cell metabolism status. Future studies should focus on the function of AhHDA1-interacting proteins and their effect on root development.
花生是一种具有高度经济重要性的农作物，但其根系生长发育的表观遗传调控尚未得到充分关注。对[相关内容]的研究表明，组蛋白去乙酰化酶（HDACs）参与细胞生长、细胞分化和应激反应。很少有研究关注HDACs在其他植物尤其是农作物根系发育中的作用。在早期研究中，我们发现花生根中组蛋白去乙酰化酶1（AhHDA1）mRNA大量积累。然而，我们并未探究AhHDA1在花生根系发育中的作用。
在本文中，我们研究了花生AhHDA1基因的作用，并重点关注其在毛状根中表达改变在表型和转录水平上的影响。我们利用发根农杆菌和RNA测序分析AhHDA1毛状根的转化，以鉴定分配到特定代谢途径的差异表达基因。将转基因毛状根用作实验材料，分析下游基因表达和组蛋白乙酰化水平。为全面了解AhHDA1功能，我们还利用酵母双杂交系统同时筛选AhHDA1相互作用蛋白。
在体外培养20天后，过表达AhHDA1的毛状根生长受到抑制，与对照和RNA干扰组相比，它们积累了更多的超氧阴离子和过氧化氢。AhHDA1在毛状根中的过表达加速了各种次生合成代谢途径的通量，同时抑制了初级代谢过程。AhHDA1过表达还导致类黄酮生物合成途径中关键酶查尔酮合酶（CHS）、异黄酮生物合成途径中羟基异黄酮合酶（HIS）以及苯丙烷生物合成途径中咖啡酰辅酶A O -甲基转移酶（CCoAOMT）编码基因的显著上调。相反，光合途径中光系统II放氧复合体多肽铁氧还蛋白1（Fd1）和核酮糖二磷酸羧化酶（RuBisCO）因AhHDA1过表达而显著下调。这些基因的表达水平与组蛋白乙酰化水平呈正相关。
我们的结果表明，基因代谢活动改变与AhHDA1过表达之间关系主要体现在类黄酮、异黄酮和苯丙烷代谢中。AhHDA1过表达阻碍了转基因毛状根的生长，可能与细胞代谢状态有关。未来研究应聚焦于AhHDA1相互作用蛋白的功能及其对根系发育的影响。
