Submitted to: Physiological and Molecular Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2005
Publication Date: 10/1/2005
Citation: Cho, S., Chen, W., Muehlbauer, F.J. 2005. Constitutive experssion of the flavanone 3-hydroxylase gene related to pathotype-specific ascochyta blight resistance in cicer arietinum l.. Physiological and Molecular Plant Pathology 67:100-107. Interpretive Summary: Ascochyta blight is a devastating disease of chickpea in nearly all production regions of the US and the world. In this research we determined that the constitutive expression of the Flavanone 3-hydroxylase gene is related to specific resistance to the disease and to the differential reactions to the two known pathotypes of the fungus present in U.S. production zones. Constitutive expression means that the products of the gene (Flavanone 3-hydroxylase) is present prior to infection by the pathogen and is produced in response to infection. This finding has important implications for the study of resistance of chickpea to this important disease. The gene for Flavanone 3-hydroxylase was mapped to linkage group 5. Additional research is needed to validate the role of this gene in conferring resistance to Ascochyta blight of chickpea.
Technical Abstract: Quantitative resistance of chickpea (Cicer arietinum L.) to a necrotrophic fungal pathogen, Ascochyta rabiei, (Pass) Labr., is conferred in a pathotype-dependent manner. Unlike race-specific or qualitative resistance, identification of genetic factors for blight resistance is difficult because diverse pathogenic and environmental factors cause significant variation in resistance patterns. To identify genes associated with blight resistance in chickpea, we conducted bulk segregation analysis of different transcript patterns between blight resistant and susceptible recombinant inbred lines (RILs) generated from a cross of PI 359075 (1) (blight susceptible) X FLIP84-92C(2) (blight resistant). Constitutive expression of a cDNA-AFLP fragment homologous to flavanone 3-hydroxylase (F3H) was lower in RILs susceptible to pathotypes I and II of A. rabiei than in RILs resistant to both pathotypes. F3H was mapped to linkage group 5. Based on expression pattern of F3H between resistant and susceptible RIL bulks, F3H or its genomic vicinity on linkage group 5 was thought to be related to blight resistance in chickpea. Further study is required to validate the genetic role of F3H and its genomic vicinity on linkage group 5 in blight resistance in chickpea.