A thaumatin-like protein of Ocimum basilicum confers tolerance to fungal pathogen and abiotic stress in transgenic Arabidopsis

作者：Misra Rajesh Chandra; Sandeep; Kamthan Mohan; Kumar Santosh; Ghosh Sumit

来源：Scientific Reports, 2016, 6(1): 25340.

DOI：10.1038/srep25340

<jats:title>Abstract</jats:title><jats:p>Plant often responds to fungal pathogens by expressing a group of proteins known as pathogenesis-related proteins (PRs). The expression of PR is mediated through pathogen-induced signal-transduction pathways that are fine-tuned by phytohormones such as methyl jasmonate (MeJA). Here, we report functional characterization of an <jats:italic>Ocimum basilicum</jats:italic> PR5 family member (<jats:italic>ObTLP1</jats:italic>) that was identified from a MeJA-responsive expression sequence tag collection. <jats:italic>ObTLP1</jats:italic> encodes a 226 amino acid polypeptide that showed sequence and structural similarities with a sweet-tasting protein thaumatin of <jats:italic>Thaumatococcus danielli</jats:italic> and also with a stress-responsive protein osmotin of <jats:italic>Nicotiana tabacum</jats:italic>. The expression of <jats:italic>ObTLP1</jats:italic> in <jats:italic>O. basilicum</jats:italic> was found to be organ-preferential under unstressed condition and responsive to biotic and abiotic stresses and multiple phytohormone elicitations. Bacterially-expressed recombinant ObTLP1 inhibited mycelial growth of the phytopathogenic fungi, <jats:italic>Scleretonia sclerotiorum</jats:italic> and <jats:italic>Botrytis cinerea</jats:italic>; thereby, suggesting its antifungal activity. Ectopic expression of <jats:italic>ObTLP1</jats:italic> in Arabidopsis led to enhanced tolerance to <jats:italic>S. sclerotiorum</jats:italic> and <jats:italic>B. cinerea</jats:italic> infections and also to dehydration and salt stress. Moreover, induced expression of the defense marker genes suggested up-regulation of the defense-response pathways in <jats:italic>ObTLP1</jats:italic>-expressing Arabidopsis upon fungal challenge. Thus, <jats:italic>ObTLP1</jats:italic> might be useful for providing tolerance to the fungal pathogens and abiotic stresses in crops.</jats:p>

• 出版日期2016-5-6