Genetic engineering & plant breeding
Masumeh Dezhabad; Hengameh Taheri; Babak Pakdaman Sardrood
Abstract
Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. lycopersici (FOL) is one of the major devastating diseases of tomato plants throughout the world. There is no information on the molecular response of tomato line, Early Urbana-Y to FOL. The present study was performed to study the line response ...
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Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. lycopersici (FOL) is one of the major devastating diseases of tomato plants throughout the world. There is no information on the molecular response of tomato line, Early Urbana-Y to FOL. The present study was performed to study the line response to FOL using phytopathological (disease severity and shoot fresh weight) as well as molecular methodologies. The transcription of several genes responsive to jasmonic acid (JA; Pin2), salicylic acid (SA; Chi3, Chi9 and PR1), the regulatory genes responsive to the signaling hormone JA (MYC2 and WRKY33) and ethylene (ET; ERF1) were studied by qRT-PCR technique at different time points after FOL inoculation (6-96 hour after inoculation). Disease symptoms development and reduced shoot fresh weight of the inoculated plants despite up-regulation of SA-dependent defense genes at different time points after pathogen infection indicated that SA signaling pathway is involved in the susceptibility of the Early Urbana-Y line to FOL. In contrast, JA and ET pathway genes were not strongly induced in response to the pathogen suggesting the involvement of JA/ET-mediated defense responses in reducing disease susceptibility. However, to gain a better understanding of enhanced resistance to fusarium wilt, more detailed molecular mechanisms underlying susceptibility of Early Urbana-Y line to FOL need to be further investigated in the future.
Masumeh Dezhabad; Hengameh Taheri; Babak Pakdaman Sardrood
Abstract
Bacillus thuringiensis Berliner as a biological control agent can play a crucial role in the integrated management of a wide range of plant pests and diseases. B. thuringiensis is expected to elicit plant defensive response through plant recognition of microbe-associated molecular patterns (MAMPs), however, ...
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Bacillus thuringiensis Berliner as a biological control agent can play a crucial role in the integrated management of a wide range of plant pests and diseases. B. thuringiensis is expected to elicit plant defensive response through plant recognition of microbe-associated molecular patterns (MAMPs), however, there is little information on the molecular base of induced systemic resistance priming of tomatoes. Using q-RT-PCR technique, the transcription rate of the genes responsive to salicylic acid, SA (Chi9, Chi3, PR1), jasmonic acid, JA (Pin2), and of the signaling regulatory genes of jasmonate/ ethylene, JA/ ET hormones (WRKY33, ERF1, MYC2) were studied at the time of 6, 12, 24, 48, 72, and 96 hours after inoculation of tomato plants with B. thuringiensis strain IBRC-M 11096 as the promoting plant growth factor. The bacterial strain could prime tomato cultivar of Early Urbana through induction of all three hormonal signaling pathways (SA, JA, and ET) involved in the resistance to a broad range of necrotrophic as well as biotrophic pathogens. However, further transcription of WRKY33, ERF1, MYC2, and Pin2 genes in the inoculated plants, indicated that the observed priming effect was mainly based on JA/ ET signaling pathway. These promising results indicate high potential of superior isolates of B. thuringiensis in the field management of the crops.