The rice immune receptor XA21 recognizes a tyrosine-sulfated protein from a Gram-negative bacterium

Abstract

A sulfated peptide activates a rice immune receptor.

Receptor Kinases in Plant-Pathogen Interactions: More Than Pattern Recognition

“…In rice (Oryza sativa), LRR-RK XA21 recognizes RaxX, a highly conserved protein in many Xanthomonas species, to trigger immune responses. RaxX21-sY, a sulfated, 21-amino acid synthetic peptide derived from RaxX, is sufficient for XA21 activation (Pruitt et al, 2015).…”

“…Indeed, the X. oryzae oryzae peptide RaxX-sY has high levels of amino acid sequence similarity to PSY1 from plants (Pruitt et al, 2015), raising the tantalizing possibility that RaxX evolved to mimic PSY1, thereby suppressing immunity (Figure 4). It will be interesting to determine whether RaxX-sY indeed mimics PSY1 in the regulation of plant growth and development and plant defenses.…”

From Chaos to Harmony: Responses and Signaling upon Microbial Pattern Recognition

“…The tyrosine-sulfated protein RaxX secreted through the type I secretion system of Xanthomonas oryzae pv. oryzae ( Xoo ) acts as a MAMP in rice (124). …”

Plant pattern-recognition receptors controlling innate immunity

“…In addition, the rice LRR-RK XA21 perceives the tyrosine-sulfated protein RaxX from Xanthomonas oryzae pv. oryzae (Xoo) species to trigger effective resistance to Xoo (Pruitt et al, 2015;Wei et al, 2016). The Arabidopsis LRR-RKs PEPR1 and PEPR2 perceive conserved Pep sequence shared by a small family of Arabidopsis ProPep proteins that are released during pathogen infection (Huffaker and Ryan, 2007;Krol et al, 2010;Yamaguchi et al, 2010).…”

“…In addition, the Lectin-RLK LecRK-VI.2 was found to act as a key modulator in plant PTI responses, although the underlying mechanism remains unknown (Singh et al, 2012). Recently, three G-type Lectin family RLKs LecRK1, LecRK2 and LecRK3 were shown to be required for brown planthopper resistance in rice (Liu et al, 2015). Broad-spectrum bacteria and insect resistance of LecRK-VI.2 in Arabidopsis and LecRK1-3 in rice indicate that Lectin-RLKs prime PTI response to both pathogen and insect attacks by either directly or indirectly perceiving conserved microbe-or insect-derived elicitors or DAMP.…”