State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China.
Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Plant Precision Breeding Academy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
Plant J. 2021 May;106(4):1116-1127. doi: 10.1111/tpj.15223. Epub 2021 Apr 5.
The floral nectary, first recognized and described by Carl Linnaeus, is a remarkable organ that serves to provide carbohydrate-rich nectar to visiting pollinators in return for gamete transfer between flowers. Therefore, the nectary has indispensable biological significance in plant reproduction and even in evolution. Only two genes, CRC and STY, have been reported to regulate floral nectary development. However, it is still unknown what genes contribute to extrafloral nectary development. Here, we report that a nectary development gene in Gossypium (GoNe), annotated as an APETALA 2/ethylene-responsive factor (AP2/ERF), is responsible for the formation of both floral and extrafloral nectaries. GoNe plants that are silenced via virus-induced gene silencing technology and/or knocked out by Cas9 produce a nectariless phenotype. Point mutation and gene truncation simultaneously in duplicated genes Ne Ne lead to impaired nectary development in tetraploid cotton. There is no difference in the expression of the CRC and STY genes between the nectary TM-1 and the nectariless MD90ne in cotton. Therefore, the GoNe gene responsible for the formation of floral and extrafloral nectaries may be independent of CRC and STY. A complex mechanism might exist that restricts the nectary to a specific position with different genetic factors. Characterization of these target genes regulating nectary production has provided insights into the development, evolution, and function of nectaries and insect-resistant breeding.
花的蜜腺，最早由卡尔·林奈（Carl Linnaeus）发现并描述，是一种显著的器官，其作用是为来访的传粉者提供富含碳水化合物的花蜜，以换取花朵之间的配子转移。因此，蜜腺在植物繁殖中具有不可或缺的生物学意义，甚至在进化中也是如此。只有两个基因，CRC 和 STY，被报道可以调节花蜜腺的发育。然而，目前尚不清楚哪些基因有助于发育额外的蜜腺。在这里，我们报告了棉属（Gossypium）中的一个蜜腺发育基因（GoNe），被注释为 APETALA 2/乙烯响应因子（AP2/ERF），它负责花和额外蜜腺的形成。通过病毒诱导的基因沉默技术沉默的 GoNe 植物和/或被 Cas9 敲除的 GoNe 植物产生无蜜 phenotype。在四倍体棉花中，同时突变和基因截断重复基因 Ne Ne 会导致蜜腺发育受损。在棉花中，蜜腺 TM-1 和无蜜 MD90ne 之间的 CRC 和 STY 基因表达没有差异。因此，负责花和额外蜜腺形成的 GoNe 基因可能独立于 CRC 和 STY。可能存在一种复杂的机制，用不同的遗传因素将蜜腺限制在特定的位置。这些调节蜜腺产生的靶基因的特征为蜜腺的发育、进化和功能以及抗虫育种提供了新的认识。
