Molecular Breeding of a Novel PTGMS Line of WDR for Broad-Spectrum Resistance to Blast Using Pi9, Pi5, and Pi54 Genes

Yi Liu,Feiming Wang,Xinqiao Yu,Guolan Liu,Junguo Bi,Zhongquan Pan,Xingxing Luo,Lijun Luo,Jiahong Wang,Deyan Kong,Fenyun Zhang,Anning Zhang

doi:10.1186/s12284-021-00537-1

Abstract

BackgroundThe two-line method based on the photoperiod and thermo-sensitive genic male sterile (PTGMS) lines is more cost-effective, simple, and efficient than the three-line system based on cytoplasmic male-sterility. Blast and drought are the most prevalent biotic and abiotic stress factors hampering rice production. Molecular techniques demonstrate higher efficacy in the pyramiding of disease resistance genes, providing green performance under the background of water-saving and drought-resistance rice.ResultsThis study employed molecular marker-assisted selection, conventional hybridization, and high-intensity stress screening to integrate three broad-spectrum blast resistance genes Pi9, Pi5, and Pi54 into Huhan 1S. Subsequently, a novel water-saving and drought-resistance rice (WDR) PTGMS line Huhan 74S was developed. The drought resistance of the new PTGMS line Huhan 74S was comparable to that of Huhan 1S. Pathogenicity assays involving the inoculation of 14 blast prevalent isolates in the glasshouse showed that the blast resistance frequency of Huhan 74S was 85.7%. Further evaluation under natural blast epidemic field conditions showed that Huhan 74S and its hybrids were resistant to leaf and neck blast. The critical temperature point of fertility-sterility alteration of Huhan 74S was 23 °C daily mean temperature. The complete male sterility under natural growth conditions in 2017 at Shanghai lasted for 67 days. Also, both the agronomic and grain quality traits met the requirement for two-line hybrid rice production.ConclusionThese results indicate that the newly bred PTGMS line Huhan 74S can be used to breed high-yielding, good-quality, disease-resistant two-line hybrid water-saving and drought-resistance rice (WDR), hence promoting sustainable rice production in China.

Highlights

Rice blast caused by Magnaporthe oryzae is a global fungal disease that severely affects rice production and grain quality
Huhan 1B (Pi9), a breeding line carrying Pi9 gene, and Huhan 91 containing Pi5 and Pi54 were the donors of rice blast resistance genes
Compared with three-line hybrid rice, the twoline hybrid rice breeding system based on photoperiod and thermo-sensitive genic male sterile (PTGMS) line has some advantages: (1) Male sterility is controlled by recessive nuclear genes, any genotype with good combining ability can be used as the male parent, a wide selection range of restorer line

Summary

Introduction

Rice blast caused by Magnaporthe oryzae is a global fungal disease that severely affects rice production and grain quality. More than 350 quantitative trait loci associated with rice blast resistance have been identified (Li et al 2020), providing a possibility of using molecular markers to detect these genes. The Pi9 gene confers broad-spectrum blast disease resistance in rice. It is located in the Piz locus together with similar genes such as Pi2, Pi50, Pigm, Piz, and Piz-t. Many successful marker-assisted introgressions using the Pi54 gene have been made in diverse backgrounds of rice varieties and hybrids (Ramalingam et al 2020; Ponnuswamy et al 2020) These blast resistance genes are significantly valuable in rice breeding for disease resistance. Molecular techniques demonstrate higher efficacy in the pyramiding of disease resistance genes, providing green performance under the background of water-saving and drought-resistance rice

Methods

Results

Discussion

Conclusion