Molecular Cytogenetic Identification of a Novel Wheat-Thinopyrum ponticum 1JS (1B) Substitution Line Resistant to Powdery Mildew and Leaf Rust.

Mingzhu Li,Honggang Wang,Xiaojuan Liu,Yanzhen Wang,Xingfeng Li,Yinguang Bao

doi:10.3389/fpls.2021.727734

Abstract

Thinopyrum ponticum (2n = 10x = 70) is a wild relative of wheat with high tolerance to both biotic and abiotic stresses; it has been wildly used in wheat genetic improvement. A disomic substitution line named SN19647 was derived from a cross between Triticum aestivum and the wheat–Th. ponticum partial amphiploid SNTE20 (2n = 8x = 56). It was evaluated for disease resistance and characterized via sequential fluorescence in situ hybridization (FISH)-genomic in situ hybridization (GISH) and molecular markers. The results showed that SN19647 carried resistance to both powdery mildew and leaf rust. It contained 42 chromosomes with a pair of wheat chromosome 1B replaced by a pair of JS chromosomes from Th. ponticum. In addition to chromosomal substitution events, structural variation also occurred on wheat chromosomes 2A, 5A, 6B, and 7B. Based on marker analysis, 19 markers specific to the JS chromosome were obtained, of which seventeen markers belonged to homoeologous group one. These results indicated that SN19647 was a 1JS (1B) substitution line. Compared with the known 1JS (1D) substitution line CH10A5, it was found that 17 markers generated different specific bands to Th. ponticum, confirming the novelty of the 1JS chromosome in SN19647. Therefore, SN19647, resistant to powdery mildew and leaf rust, was a novel 1JS (1B) substitution line that can be used in wheat genetic improvement.

Highlights

Wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD) is cultivated in diverse geographical regions, environments, and production systems, occupying approximately 220 million ha worldwide (Singh et al, 2016)
SN19647 and its parents were inoculated with the Blumeria graminis f. sp. tritici (Bgt) isolate E09, the disease reaction was assessed once the susceptible control HXH was thoroughly infected
The results showed that Th. ponticum, SNTE20, JM22 and SN19647 were all resistant with an infection types (ITs) score of 0

Summary

Introduction

Wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD) is cultivated in diverse geographical regions, environments, and production systems, occupying approximately 220 million ha worldwide (Singh et al, 2016). With the global population estimated to exceed 9 billion by 2050, a 1.6% annual increase in wheat production has been expected to satisfy the increasing population, with the projection of an enhanced yield from 3 to 5 tons/ha (Tilman et al, 2002; Singh et al, 2016). Climate change and disease occurrence are threatening wheat productivity (Price et al, 2013; Curtis and Halford, 2014; Lobell, 2019). A Novel 1JS (1B) Substitution Line Marker types Numbers

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Conclusion