Maize ANT1 modulates vascular development, chloroplast development, photosynthesis, and plant growth
Maize ANT1 modulates vascular development, chloroplast development, photosynthesis, and plant growth
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DOI：
10.1073/pnas.2012245117
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发表时间：
2020-09-01
影响因子：
11.1
通讯作者：
Li, Wen-Hsiung
中科院分区：
文献类型：
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作者：
Liu, Wen-Yu;Lin, Hsin-Hung;Li, Wen-Hsiung
拟南芥（Arabidopsis AINTEGUMENTA， ANT）是一种AP2转录因子，控制植物生长和花器官发生。在本研究中，我们对玉米胚叶的转录组分析和原位杂交实验表明，玉米ANT1 （ZmANT1）调控维管发育。为了更好地了解ANTI的功能，我们确定了ZmANT1的结合基序，然后发现ZmANT1结合了谷子SCR1、GNC和AN3的启动子，这三个启动子分别是Kranz解剖、叶绿体发育和植物生长的关键调控因子。我们利用CRISPR/Cas9技术在C4谷子毒尾草中产生了一个单密码子缺失的突变体和两个ANT1同源的移码突变体。这两个移码突变体的光合效率和生长速率均低于野生型（WT），叶片较小，籽粒产量较低。叶片偶有克兰兹解剖和叶脉间距扭曲的现象。通过对WT和三个突变体发育叶片的转录组学分析，我们在两个移码突变系中发现了差异表达基因（deg），并发现许多下调的deg在光合作用、血红素、四氯结合和抗氧化活性中富集。此外，我们预测了ZmANT1的许多靶基因，并选择了其中的13个基因来确认ZmANT1与其启动子的结合。基于以上观察结果，我们提出了ANT1通过其靶基因调控细胞增殖和叶片生长、维管和静脉发育、叶绿体发育和光合作用的模型。我们的研究揭示了ANT1在植物生长和花器官发生过程中的生物学作用。
Arabidopsis AINTEGUMENTA (ANT), an AP2 transcription factor, is known to control plant growth and floral organogenesis. In this study, our transcriptome analysis and in situ hybridization assays of maize embryonic leaves suggested that maize ANT1 (ZmANT1) regulates vascular development. To better understand ANTI functions, we determined the binding motif of ZmANT1 and then showed that ZmANT1 binds the promoters of millet SCR1, GNC, and AN3, which are key regulators of Kranz anatomy, chloroplast development, and plant growth, respectively. We generated a mutant with a single-codon deletion and two frameshift mutants of the ANT1 ortholog in the C4 millet Setaria viridis by the CRISPR/Cas9 technique. The two frameshift mutants displayed reduced photosynthesis efficiency and growth rate, smaller leaves, and lower grain yields than wild-type (WT) plants. Moreover, their leaves sporadically exhibited distorted Kranz anatomy and vein spacing. Conducting transcriptomic analysis of developing leaves in the WT and the three mutants we identified differentially expressed genes (DEGs) in the two frameshift mutant lines and found many downregulated DEGs enriched in photosynthesis, heme, tetrapyrrole binding, and antioxidant activity. In addition, we predicted many target genes of ZmANT1 and chose 13 of them to confirm binding of ZmANT1 to their promoters. Based on the above observations, we proposed a model for ANT1 regulation of cell proliferation and leaf growth, vascular and vein development, chloroplast development, and photosynthesis through its target genes. Our study revealed biological roles of ANT1 in several developmental processes beyond its known roles in plant growth and floral organogenesis.