Infection processes of xylem-colonizing pathogenic bacteria: possible explanations for the scarcity of qualitative disease resistance genes against them in crops.
Disease resistance against xylem-colonizing pathogenic bacteria in crops. Plant pathogenic bacteria cause destructive diseases in many commercially important crops. Among these bacteria, eight pathogens, Ralstonia solanacearum, Xanthomonas oryzae pv. oryzae, X. campestris pv. campestris, Erwinia amylovora, Pantoea stewartii subsp. stewartii, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. actinidiae, and Xylella fastidiosa, infect their host plants through different infection sites and paths and eventually colonize the xylem tissues of their host plants, resulting in wilting symptoms by blocking water flow or necrosis of xylem tissues. Noticeably, only a relatively small number of resistant cultivars in major crops against these vascular bacterial pathogens except X. oryzae pv. oryzae have been found or generated so far, although these pathogens threaten productivity of major crops. In this review, we summarize the lifestyles of major xylem-colonizing bacterial pathogens and then discuss the progress of current research on disease resistance controlled by qualitative disease resistance genes or quantitative trait loci against them. Finally, we propose infection processes of xylem-colonizing bacterial pathogens as one of possible reasons for why so few qualitative disease resistance genes against these pathogens have been developed or identified so far in crops.
Department of Horticultural Biotechnology and Institute of Life Science and Resources, College of Life Science, Kyung Hee University, Yongin, 446-701, Korea.
Chungyun
C
Bae
Sang Wook
SW
Han
Yu-Rim
YR
Song
Bo-Young
BY
Kim
Hyung-Jin
HJ
Lee
Je-Min
JM
Lee
Inhwa
I
Yeam
Sunggi
S
Heu
Chang-Sik
CS
Oh
D001419:Bacteria / Q000472:pathogenicity*; D018556:Crops, Agricultural / Q000235:genetics* / Q000382:microbiology; D060467:Disease Resistance / Q000235:genetics*; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D040641:Quantitative Trait Loci; D014774:Virulence; D052584:Xylem / Q000382:microbiology*