Resistant and susceptible responses in tomato to cyst nematode are differentially regulated by salicylic acid.
To understand the machinery underlying a tomato cultivar harboring the Hero A gene against cyst nematode using microarrays, we first analyzed tomato gene expression in response to potato cyst nematode (PCN; Globodera rostochiensis) during the early incompatible and compatible interactions at 3 and 7 days post-inoculation (dpi). Transcript levels of the phenylalanine ammonia lyase (PAL) and Myb-related genes were up-regulated at 3 dpi in the incompatible interaction. Transcription of the genes encoding pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) was also up-regulated at 3 dpi in the incompatible interaction. On the other hand, the four genes (PAL, Myb, PDC and ADH) were down-regulated in the compatible interaction at 3 dpi. When the expression levels of several pathogenesis-related (PR) protein genes in tomato roots were compared between the incompatible and compatible interactions, the salicylic acid (SA)-dependent PR genes were found to be induced in the incompatible interaction at 3 dpi. The PR-1(P4) transcript increased to an exceptionally high level at 3 dpi in the cyst nematode-infected resistant plants compared with the uninoculated controls. The free SA levels were elevated to similar levels in both incompatible and compatible interactions. We then confirmed that PR-1(P4) was not significantly induced in the NahG tomato harboring the Hero A gene, compared with the resistant cultivar. We thus found that PR-1(P4) was a hallmark for the cultivar resistance conferred by Hero A against PCN and that nematode parasitism resulted in the inhibition of the SA signaling pathway in the susceptible cultivars.
Uehara
Taketo
T
National Agricultural Research Center for Hokkaido Region, 1 Hitsujigaoka, Toyohira-ku, Sapporo 062-8555, Japan. uehara@affrc.go.jp
Sugiyama
Shunpei
S
Matsuura
Hideyuki
H
Arie
Tsutomu
T
Masuta
Chikara
C
D000818:Animals; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism* / Q000469:parasitology; D020411:Oligonucleotide Array Sequence Analysis; D010935:Plant Diseases / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020156:Salicylic Acid / Q000378:metabolism*; D015398:Signal Transduction; D014431:Tylenchoidea / Q000502:physiology*
D010940:Plant Proteins; D018749:RNA, Plant; C053376:pathogenesis-related proteins, plant; D020156:Salicylic Acid