Developing disease‐resistant thermosensitive male sterile rice by multiplex gene editing

Abstract

Summary High‐quality and disease‐resistant male sterile lines have great potential for applications in hybrid rice breeding. We introduced specific mutations into the TMS5, Pi21, and Xa13 genes in Pinzhan intermediate breeding material using the CRISPR/Cas9 multiplex genome editing system. We found that the transgene‐free homozygous triple tms5/pi21/xa13 mutants obtained in the T1 generation displayed characteristics of thermosensitive genic male sterility (TGMS) with enhanced resistance to rice blast and bacterial blight. Our study provides a convenient and effective way of converting breeding intermediate material into TGMS lines through multiplex gene editing, which could significantly accelerate the breeding of sterile lines.

Sclerenchyma cell thickening through enhanced lignification induced by OsMYB30 prevents fungal penetration of rice leaves

“…Rice blast disease, caused by Magnaporthe oryzae , is the most devastating disease in rice, causing an estimated US$66 billion global annual loss, enough to feed 60 million people (Zhao et al , 2018). Due to its importance, great efforts have been made to study the rice– M. oryzae interaction, leading to many advances in our understanding of M. oryzae pathogenesis and host resistance (Li et al , 2019a,b). In fact, the rice– M. oryzae pathosystem has also become a premier system for studying plant–pathogen interaction.…”

“…Currently, c. 100 blast resistance ( R ) genes have been identified and 41 of these (including allelic R genes) have been isolated (Li et al , 2019a,b). Most of these belong to nucleotide‐binding domain leucine‐rich repeat containing (NLR) genes, and confer race‐specific blast resistance, with the exceptions of Pigm (Deng et al , 2017), Pi7 (Campbell et al , 2004), Pi9 (Qu et al , 2006), and Pi57 (Dong et al , 2017).…”

“…Most of these belong to nucleotide‐binding domain leucine‐rich repeat containing (NLR) genes, and confer race‐specific blast resistance, with the exceptions of Pigm (Deng et al , 2017), Pi7 (Campbell et al , 2004), Pi9 (Qu et al , 2006), and Pi57 (Dong et al , 2017). In addition, due to fierce competition between host and pathogen, the resistance mediated by most NLR genes is not durable (Devi et al , 2015; Li et al , 2019a,b). Recently, some defence‐related ( DR ) genes that do not fall into typical NLR category have been shown to confer broad‐spectrum resistance (Li et al , 2019a,b).…”

“…In addition, due to fierce competition between host and pathogen, the resistance mediated by most NLR genes is not durable (Devi et al , 2015; Li et al , 2019a,b). Recently, some defence‐related ( DR ) genes that do not fall into typical NLR category have been shown to confer broad‐spectrum resistance (Li et al , 2019a,b). For example, pi21 , with function loss of the encoding proline‐ and cysteine‐rich protein (Fukuoka et al , 2009), and Ptr , encoding an armadillo‐repeats‐containing protein, is required for broad‐spectrum blast resistance (Zhao et al , 2018); but neither proteins have been characterised in biochemical function.…”

Strategies for Breeding Durable Resistance to Rice Blast Using pi21

“…The lower survival rate of plants whose Pi21 expression is strongly suppressed by RNAi is in line with this hypothesis (S. Fukuoka, unpublished data). A recent study reported increased blast resistance conferred by a CRISPR/Cas9-edited Pi21 gene [50]. Characterization of the agronomic traits of lines having diverse Pi21 variants will provide further evidence on this topic.…”