Key Laboratory of Coarse Cereal Processing Ministry of Agriculture and Rural Affairs, College of Pharmacy and Biological Engineering, Chengdu University, Chengdu 610106, PR China; National Research and Development Center for Coarse Cereal Processing, College of Pharmacy and Biological Engineering, Chengdu University, Chengdu 610106, PR China.
Key Laboratory of Coarse Cereal Processing Ministry of Agriculture and Rural Affairs, College of Pharmacy and Biological Engineering, Chengdu University, Chengdu 610106, PR China; National Research and Development Center for Coarse Cereal Processing, College of Pharmacy and Biological Engineering, Chengdu University, Chengdu 610106, PR China.
Plant Physiol Biochem. 2020 Jun;151:443-456. doi: 10.1016/j.plaphy.2020.03.050. Epub 2020 Apr 3.
Chenopodium quinoa, a halophytic crop belonging to the Amaranthaceae, has remarkable resistance to harsh growth conditions and produces seed with excellent nutritional value. This makes it a suitable crop for marginal soils. However, to date most of the commercial cultivars are susceptible to preharvest sprouting (PHS). Meanwhile, understanding of the PHS regulatory mechanisms is still limited. Abscisic acid (ABA) has been demonstrated to be tightly associated with seed dormancy and germination regulation in many crops. Whether ABA metabolism pathway could be manipulated to prevent PHS in quinoa is worth investigating. In the present study, we tested the inhibitory effects of exogenous ABA on quinoa seed germination. By RNA-seq analysis we investigated the global gene expression changes during seed germination, and obtained 1066 ABA-repressed and 392 ABA-induced genes. Cis-elements enrichment analysis indicated that the promoters of these genes were highly enriched in motifs "AAAAAAAA" and "ACGTGKC (K = G/T)", the specific binding motifs of ABI3/VP1 and ABI5. Transcription factor annotation showed that 13 genes in bHLH, MADS-box, G2-like and NF-YB, and five genes in B3, bZIP, GATA and LBD families were specifically ABA-repressed and -induced, respectively. Furthermore, expression levels of 53 key homologs involved in seed dormancy and germination regulation were markedly changed. Hence, we speculated that the 18 transcription factors and the homologs were potential candidates involved in ABA-mediated seed dormancy and germination regulation, which could be manipulated for molecular breeding of quinoa elites with PHS tolerance in future.
藜麦，一种属于苋科的盐生作物，具有很强的抗恶劣生长条件的能力，并能生产出具有优异营养价值的种子。这使得它成为边缘土壤的理想作物。然而，迄今为止，大多数商业品种都容易遭受收获前发芽（PHS）。同时，对 PHS 调控机制的理解仍然有限。脱落酸（ABA）已被证明与许多作物的种子休眠和萌发调控密切相关。是否可以操纵 ABA 代谢途径来防止藜麦的 PHS 值得研究。在本研究中，我们测试了外源 ABA 对藜麦种子萌发的抑制作用。通过 RNA-seq 分析，我们研究了种子萌发过程中的全基因表达变化，获得了 1066 个 ABA 抑制和 392 个 ABA 诱导的基因。顺式元件富集分析表明，这些基因的启动子高度富集于“AAAAAAAA”和“ACGTGKC（K = G/T）”的基序中，这是 ABI3/VP1 和 ABI5 的特异性结合基序。转录因子注释表明，bHLH、MADS-box、G2-like 和 NF-YB 中的 13 个基因和 B3、bZIP、GATA 和 LBD 家族中的 5 个基因分别特异性地被 ABA 抑制和诱导。此外，参与种子休眠和萌发调控的 53 个关键同源物的表达水平明显发生了变化。因此，我们推测这 18 个转录因子和同源物是潜在的候选基因，参与 ABA 介导的种子休眠和萌发调控，这可以为未来具有 PHS 耐受性的藜麦精英的分子育种提供参考。
