A silent exonic mutation in a rice integrin-α FG-GAP repeat-containing gene causes male-sterility by affecting mRNA splicing

Ting Zou #; Dan Zhou #; Wenjie Li #; Guoqiang Yuan; Yang Tao; Zhiyuan He; Xu Zhang; Qiming Deng; Shiquan Wang; Aiping Zheng; Jun Zhu; Yueyang Liang; Huainian Liu; Aijun Wang; Lingxia Wang; Ping Li *; Shuangcheng Li *

International Journal of Molecular Sciences（IF=4.556）,  2020 ，21（6）

https://www.mdpi.com/1422-0067/21/6/2018/htm

Abstract

Pollen development plays crucial roles in the life cycle of higher plants. Here we characterized a rice mutant with complete male-sterile phenotype, pollen-less 1 (pl1). pl1 exhibited smaller anthers with arrested pollen development, absent Ubisch bodies, necrosis-like tapetal hypertrophy, and smooth anther cuticular surface. Molecular mapping revealed a synonymous mutation in the fourth exon of PL1 co-segregated with the mutant phenotype. This mutation disrupts the exon-intron splice junction in PL1, generating aberrant mRNA species and truncated proteins. PL1 is highly expressed in the tapetal cells of developing anther, and its protein is co-localized with plasma membrane (PM) and endoplasmic reticulum (ER) signal. PL1 encodes an integrin-α FG-GAP repeat-containing protein, which has seven β-sheets and putative Ca2+-binding motifs and is broadly conserved in terrestrial plants. Our findings therefore provide insights into both the role of integrin-α FG-GAP repeat-containing protein in rice male fertility and the influence of exonic mutation on intronic splice donor site selection.

Keywords:  RNA splicing; PL1; rice (Oryza sativa L.); anther; pollen; male sterility; integrin-α FG-GAP repeat-containing protein