@article{fdi:010068716,
  title = {{M}utations in {R}ice yellow mottle virus polyprotein {P}2a involved in {RYMV}2 gene resistance breakdown},
  author = {{G}alzi, {A}gn{\`e}s and {D}ubreuil {T}ranchant, {C}hristine and {H}{\'e}brard, {E}ug{\'e}nie and {M}ariac, {C}{\'e}dric and {G}hesqui{\`e}re, {A}lain and {A}lbar, {L}aurence},
  editor = {},
  language = {{ENG}},
  abstract = {{R}ice yellow mottle virus ({RYMV}) is one of the major diseases of rice in {A}frica. {T}he high resistance of the {O}ryza glaberrima {T}og7291 accession involves a null allele of the {RYMV}2 gene, whose ortholog in {A}rabidopsis, {CPR}5, is a transmembrane nucleoporin involved in effector-triggered immunity. {T}o optimize field deployment of the {RYMV}2 gene and improve its durability, which is often a weak point in varietal resistance, we analyzed its efficiency toward {RYMV} isolates representing the genetic diversity of the virus and the molecular basis of resistance breakdown. {T}og7291 resistance efficiency was highly variable depending on the isolate used, with infection rates ranging from 0 to 98% of plants. {B}ack-inoculation experiments indicated that infection cases were not due to an incomplete resistance phenotype but to the emergence of resistance breaking ({RB}) variants. {I}nterestingly, the capacity of the virus to overcome {T}og7291 resistance is associated with a polymorphism at amino-acid 49 of the {VP}g protein which also affects capacity to overcome the previously studied {RYMV}1 resistance gene. {T}his polymorphism appeared to be a main determinant of the emergence of {RB} variants. {I}t acts independently of the resistance gene and rather reflects inter-species adaptation with potential consequences for the durability of resistance. {RB} mutations were identified by full-length or partial sequencing of the {RYMV} genome in infected {T}og7291 plants and were validated by directed mutagenesis of an infectious viral clone. {W}e found that {T}og7291 resistance breakdown involved mutations in the putative membrane anchor domain of the polyprotein {P}2a. {A}lthough the precise effect of these mutations on rice/{RYMV} interaction is still unknown, our results offer a new perspective for the understanding of {RYMV}2 mediated resistance mechanisms. {I}nterestingly, in the susceptible {IR}64 variety, {RB} variants showed low infectivity and frequent reversion to the wild-type genotype, suggesting that {T}og7291 resistance breakdown is associated with a major loss of viral fitness in normally susceptible {O}. sativa varieties. {D}espite the high frequency of resistance breakdown in controlled conditions, this loss of fitness is an encouraging element with regards to {RYMV}2 resistance durability.},
  keywords = {rice ; {RYMV} ; {CPR}5 ; resistance breakdown ; virus adaptation ; deep ; sequencing},
  booktitle = {},
  journal = {{F}rontiers in {P}lant {S}cience},
  volume = {7},
  numero = {},
  pages = {1779 [11 ]},
  ISSN = {1664-462{X}},
  year = {2016},
  DOI = {10.3389/fpls.2016.01779},
  URL = {https://www.documentation.ird.fr/hor/fdi:010068716},
}