RETRACTED: A Strain of an Emerging Indian Xanthomonas oryzae pv. oryzae Pathotype Defeats the Rice Bacterial Blight Resistance Gene xa13 Without Inducing a Clade III SWEET Gene and Is Nearly Identical to a Recent Thai Isolate

Abstract

The rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) injects transcription activator-like effectors (TALEs) that bind and activate host “susceptibility” (S) genes important for disease. Clade III SWEET genes are major S genes for bacterial blight. The resistance genes xa5, which reduces TALE activity generally, and xa13, a SWEET11 allele not recognized by the cognate TALE, have been effectively deployed. However, strains that defeat both resistance genes individually were recently reported in India and Thailand. To gain insight into the mechanism(s), we completely sequenced the genome of one such strain from each country and examined the encoded TALEs. Strikingly, the two strains are clones, sharing nearly identical TALE repertoires, including a TALE known to activate SWEET11 strongly enough to be effective even when diminished by xa5. We next investigated SWEET gene induction by the Indian strain. The Indian strain induced no clade III SWEET in plants harboring xa13, indicating a pathogen adaptation that relieves dependence on these genes for susceptibility. The findings open a door to mechanistic understanding of the role SWEET genes play in susceptibility and illustrate the importance of complete genome sequence-based monitoring of Xoo populations in developing varieties with effective disease resistance.

Precise CRISPR-Cas9 Mediated Genome Editing in Super Basmati Rice for Resistance Against Bacterial Blight by Targeting the Major Susceptibility Gene

“…It has been reported that Xa41(t) (having 18 bp deletion) offers broad-spectrum resistance against a large collection of Xoo strains (Hutin et al, 2015b). Recently it was reported that some Xoo strains still cause infection in rice despite R genes (Carpenter et al, 2018;Doucouré et al, 2018). These failures have prompted plant genome engineers to develop resistance against this rapidly evolving pathogen by mutating susceptibility genes.…”

Population genomics and pathotypic evaluation of the bacterial leaf blight pathogen of rice reveals rapid evolutionary dynamics of a plant pathogen

“…R gene xa5 showed very good resistance (above 95%) to Xoo from all lineages. Previously, isolates of Xoo having compatibility with xa5 were only reported from Indian Lineages IX-I and IX-III, and some Philipps and Korea isolates (35, 55–57). The only 2 Chinese Xoo from Yunnan province (YN24 and YN04-5) belonging to IX-I and IX-III showed good infection ability to rice with xa5 , suggesting putative transmission of Xoo from India to South China.…”

Role of transporters in plant disease resistance

“…The positive regulatory nature of SWEET s was reported in rice and cotton against the blight pathogen X. citri . In rice, the recessive resistance genes xa13 and xa25 are the mutant forms of SWEET11 and SWEET14 , respectively, and play a positive role in resistance against Xoo (Carpenter et al, 2018). In cotton, the recessive gene b6 (a homolog of SWEET gene) is involved in the resistance response against X. citri in the Acb6 line (Acala‐44 cotton line with the b6 gene; Cox et al, 2017).…”