Department of Biology, New Mexico State University, 1200 S. Horseshoe Dr, Las Cruces, NM, 88003, USA.
Division of Plant Sciences, University of Missouri, Waters Hall 1112 University Ave, Columbia, MO, 65201, USA.
Plant Reprod. 2020 Dec;33(3-4):159-171. doi: 10.1007/s00497-020-00392-y. Epub 2020 Aug 29.
Members of the Brassicaceae family have the ability to regulate pollination events occurring on the stigma surface. In Brassica species, self-pollination leads to an allele-specific interaction between the pollen small cysteine-rich peptide ligand (SCR/SP11) and the stigmatic S-receptor kinase (SRK) that activates the E3 ubiquitin ligase ARC1 (Armadillo repeat-containing 1), resulting in proteasomal degradation of various compatibility factors including glyoxalase I (GLO1) which is necessary for successful pollination. In Brassica napus, the suppression of GLO1 was sufficient to reduce compatibility, and overexpression of GLO1 in self-incompatible Brassica napus stigmas resulted in partial breakdown of the self-incompatibility response. Here, we verified if BnGLO1 could function as a compatibility factor in the artificial self-incompatibility system of Arabidopsis thaliana expressing AlSCR, AlSRK and AlARC1 proteins from A. lyrata. Overexpression of BnGLO1 is sufficient to breakdown self-incompatibility response in A. thaliana stigmas. Therefore, GLO1 has an indisputable role as a compatibility factor in the stigma in regulating pollen attachment and pollen tube growth. Lastly, this study demonstrates the usefulness of an artificial self-incompatibility system in A. thaliana for interspecific self-incompatibility studies.
芸薹属植物家族的成员具有调节柱头表面授粉事件的能力。在芸薹属物种中，自花授粉导致花粉小半胱氨酸丰富肽配体（SCR/SP11）与柱头 S 受体激酶（SRK）之间的等位基因特异性相互作用，激活 E3 泛素连接酶 ARC1（富含 Armadillo 重复的 1），导致包括糖氧酶 I（GLO1）在内的各种亲和因子的蛋白酶体降解，GLO1 对于成功授粉是必需的。在甘蓝型油菜中，GLO1 的抑制足以降低亲和性，而在自不亲和的甘蓝型油菜柱头上过表达 GLO1 导致自不亲和反应部分破坏。在这里，我们验证了 BnGLO1 是否可以作为拟南芥表达来自 A. lyrata 的 AlSCR、AlSRK 和 AlARC1 蛋白的人工自交不亲和系统中的亲和因子发挥作用。BnGLO1 的过表达足以破坏拟南芥柱头中的自交不亲和反应。因此，GLO1 作为柱头中调节花粉附着和花粉管生长的亲和因子具有不可争议的作用。最后，本研究证明了拟南芥人工自交不亲和系统在种间自交不亲和研究中的有用性。
