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Article|01 Aug 2021|OPEN
Molecular characteristics of S-RNase alleles as the determinant of self-incompatibility in the style of Fragaria viridis
Jianke Du1,2 , Chunfeng Ge1,3 , Tingting Li1 , Sanhong Wang1 and Zhihong Gao1 , Hidenori Sassa2 , Yushan Qiao,1 ,
1Laboratory of Fruit Crop Biotechnology, College of Horticulture, Nanjing Agricultural University, Nanjing 210095 Jiangsu, China
2Laboratory of Genetics and Plant Breeding, Graduate School of Horticulture, Chiba University, Matsudo 271-8510 Chiba, Japan
3Present address: Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing 210014 Jiangsu, China
*Corresponding author. E-mail: qiaoyushan@njau.edu.cn

Horticulture Research 8,
Article number: 185 (2021)
doi: https://doi.org/10.1038/s41438-021-00623-x
Views: 661

Received: 12 Jan 2021
Revised: 29 May 2021
Accepted: 01 Jun 2021
Published online: 01 Aug 2021

Abstract

Strawberry (Fragaria spp.) is a member of the Rosoideae subfamily in the family Rosaceae. The self-incompatibility (SI) of some diploid species is a key agronomic trait that acts as a basic pollination barrier; however, the genetic mechanism underlying SI control in strawberry remains unclear. Two candidate S-RNases (Sa- and Sb-RNase) identified in the transcriptome of the styles of the self-incompatible Fragaria viridis 42 were confirmed to be SI determinants at the S locus following genotype identification and intraspecific hybridization using selfing progenies. Whole-genome collinearity and RNase T2 family analysis revealed that only an S locus exists in Fragaria; however, none of the compatible species contained S-RNase. Although the results of interspecific hybridization experiments showed that F. viridis (SI) styles could accept pollen from F. mandshurica (self-compatible), the reciprocal cross was incompatible. Sa and Sb-RNase contain large introns, and their noncoding sequences (promotors and introns) can be transcribed into long noncoding RNAs (lncRNAs). Overall, the genus Fragaria exhibits S-RNase-based gametophytic SI, and S-RNase loss occurs at the S locus of compatible germplasms. In addition, a type of SI-independent unilateral incompatibility exists between compatible and incompatible Fragaria species. Furthermore, the large introns and neighboring lncRNAs in S-RNase in Fragaria could offer clues about S-RNase expression strategies.