title: Salicylic acid-mediated establishment of the compatibility between Alternaria brassicicola and Brassica juncea is mitigated by abscisic acid in Sinapis alba.
abstract: This work addresses the changes in the phytohormonal signature in the recognition of the necrotrophic fungal pathogen Alternaria brassicicola by susceptible Brassica juncea and resistant Sinapis alba. Although B. juncea, S. alba and Arabidopsis all belong to the same family, Brassicaceae, the phytohormonal response of susceptible B. juncea towards this pathogen is unique because the latter two species express non-host resistance. The differential expression of the PR1 gene and the increased level of salicylic acid (SA) indicated that an SA-mediated biotrophic mode of defence response was triggered in B. juncea upon challenge with the pathogen. Compared to B. juncea, resistant S. alba initiated enhanced abscisic acid (ABA) and jasmonic acid (JA) responses following challenge with this pathogen, as revealed by monitoring the expression of ABA-related genes along with the concentration of ABA and JA. Furthermore, these results were verified by the exogenous application of ABA on B. juncea leaves prior to challenge with A. brassicicola, which resulted in a delayed disease progression, followed by the inhibition of the pathogen-mediated increase in SA response and enhanced JA levels. Therefore, it seems that A. brassicicola is steering the defence response towards a biotrophic mode by mounting an SA response in susceptible B. juncea, whereas the enhanced ABA response of S. alba not only counteracts the SA response but also restores the necrotrophic mode of resistance by enhancing JA biosynthesis.
authors.affiliation: Division of Plant Biology, Bose Institute, P1/12 C. I. T. Scheme VIIM, Kolkata 700054, West Bengal, India. mrinmoy_mazumder82@yahoo.co.in
authors.forename: Mrinmoy
authors.initials: M
authors.lastname: Mazumder
authors.forename: Srirupa
authors.initials: S
authors.lastname: Das
authors.forename: Upala
authors.initials: U
authors.lastname: Saha
authors.forename: Madhuvanti
authors.initials: M
authors.lastname: Chatterjee
authors.forename: Kaushik
authors.initials: K
authors.lastname: Bannerjee
authors.forename: Debabrata
authors.initials: D
authors.lastname: Basu
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D000528:Alternaria; D060467:Disease Resistance; D015870:Gene Expression; D017343:Genes, Plant; D009149:Mustard Plant / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D010937:Plant Growth Regulators / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism*; D031226:Sinapis / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*
chemical_list: D010937:Plant Growth Regulators; D010940:Plant Proteins; D000040:Abscisic Acid; D020156:Salicylic Acid
keywords: Abscisic acid; Alternaria brassicicola; Brassica juncea; Jasmonic acid; Necrotrophic pathogen; Salicylic acid; Sinapis alba