Differential Induction of the Arabidopsis thaliana Thi2.1 Gene by Fusarium oxysporum f. sp. matthiolae

Abstract

The Arabidopsis thaliana Thi2.1 gene is inducible by necrotrophic fungi through a signal transduction pathway different from that for pathogenesis-related (PR) proteins. We have identified three ecotypes that are susceptible (Col-2, Ler, and Ws) and two ecotypes that are resistant (Mt-0 and Uk-4) to spray inoculation with Fusarium oxysporum f. sp. matthiolae. The Thi2.1 transcript level after infection correlates with resistance, being 5 to 10 times higher in the resistant than in the susceptible ecotypes. The beta-glucuronidase (GUS) expression of a Thi2.1-promoter-uidA fusion (with a promoter derived from Col-2) is on the average almost 10 times higher in the Uk-4 background than in the Col-2 background. This confirms the results obtained by Northern (RNA) blots and indicates that Uk-4, and probably other resistant ecotypes too, might have a more sensitive recognition system for F. oxysporum f. sp. matthiolae or might have a signal transduction system that gives a higher amplification of the original recognition signal. Our results suggest a role of the Thi2.1 gene in resistance against F. oxysporum f. sp. matthiolae and perhaps other necrotrophic fungi.

Factors modulating the levels of the allelochemical sorgoleone in Sorghum bicolor

“…Exposing plants to Actigard, a salicylic acid-like elicitor of SAR (Inbar et al 1998), significantly repressed sorgoleone production (Table 2). Treating plants with chitin, which is known to induce the expression of SAR genes (Hahn 1996;Zhang et al 2002), or Messenger, which is known to induce expression of plant defense genes such as PR1, PR2, PDF1.2, and Thi2.1 (Biesgen and Weiler 1999;Brown et al 2003;Epple et al 1998), did not have a significant effect on sorgoleone production. Plants exposed to the more complex harpin-based elicitor ProAct had only slightly higher levels of sorgoleone.…”

The Lateral Organ Boundaries Domain Transcription Factor LBD20 Functions in Fusarium Wilt Susceptibility and Jasmonate Signaling in Arabidopsis

“…5). This defense gene subset included that encoding the antifungal protein Thi2.1 known to reduce disease severity to F. oxysporum (Epple et al, 1997(Epple et al, , 1998) and the antiinsect and wound-responsive protein VSP2, while no regulatory effect was observed on the plant defensin marker gene PDF1.2. The chlorosis and senescence-like response elicited by application of F. oxysporum culture filtrate was also reduced in lbd20 (Fig.…”

The families of pathogenesis-related proteins, their activities, and comparative analysis of PR-1 type proteins

“…matthiolae (Fom) [8]. Moreover, overexpression of the JAinducible thionin gene thi2n1 increased SA-independent resistance against Fom [21,22]. These results suggest that the SA-and JA-dependent defense pathways in Arabidopsis contribute to resistance against distinct microbial pathogens.…”