State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
State Key Lab of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China.
Nat Commun. 2023 Feb 14;14(1):836. doi: 10.1038/s41467-023-36271-z.
Wheat (Triticum aestivum L.) is a major staple food for more than one-third of the world's population. Tiller number is an important agronomic trait in wheat, but only few related genes have been cloned. Here, we isolate a wheat mutant, tiller number1 (tn1), with much fewer tillers. We clone the TN1 gene via map-based cloning: TN1 encodes an ankyrin repeat protein with a transmembrane domain (ANK-TM). We show that a single amino acid substitution in the third conserved ankyrin repeat domain causes the decreased tiller number of tn1 mutant plants. Resequencing and haplotype analysis indicate that TN1 is conserved in wheat landraces and modern cultivars. Further, we reveal that the expression level of the abscisic acid (ABA) biosynthetic gene TaNCED3 and ABA content are significantly increased in the shoot base and tiller bud of the tn1 mutants; TN1 but not tn1 could inhibit the binding of TaPYL to TaPP2C via direct interaction with TaPYL. Taken together, we clone a key wheat tiller number regulatory gene TN1, which promotes tiller bud outgrowth probably through inhibiting ABA biosynthesis and signaling.
小麦（Triticum aestivum L.）是全球超过三分之一人口的主要主食。分蘖数是小麦的一个重要农艺性状，但只有少数相关基因被克隆。在这里，我们分离到一个分蘖数较少的小麦突变体，分蘖数 1（tn1）。我们通过图谱定位克隆克隆了 TN1 基因：TN1 编码一个具有跨膜结构域的锚蛋白重复蛋白（ANK-TM）。我们发现，tn1 突变体中第三个保守锚蛋白重复结构域中的一个单一氨基酸取代导致分蘖数减少。重测序和单倍型分析表明，TN1 在小麦地方品种和现代品种中是保守的。此外，我们揭示了 tn1 突变体中 shoot base 和分蘖芽中的脱落酸（ABA）生物合成基因 TaNCED3 和 ABA 含量的表达水平显著增加；TN1 而非 tn1 可以通过与 TaPYL 的直接相互作用抑制 TaPYL 与 TaPP2C 的结合。综上所述，我们克隆了一个关键的小麦分蘖数调控基因 TN1，它可能通过抑制 ABA 生物合成和信号转导来促进分蘖芽的生长。
