Molecular and Pathogenic Characterization ofFusarium redolens, a New Causal Agent of Fusarium Yellows in Chickpea

Abstract

The association of Fusarium redolens with wilting-like symptoms in chickpea in Lebanon, Morocco, Pakistan, and Spain is reported for the first time, together with the molecular and pathogenic characterization of isolates of the pathogen from chickpea of diverse geographic origin. Maximum parsimony analysis of sequences of the translation elongation factor 1α (TEF-1α) gene grouped all F. redolens isolates from chickpea in the same main clade. Pathogenicity assays using three chickpea cultivars and isolates from different geographic origins indicated that F. redolens is mildly virulent on chickpea. Moreover, infection of chickpea by F. redolens induces a disease syndrome similar to that caused by the yellowing pathotype of F. oxysporum f. sp. ciceris, including leaf yellowing and necrosis that develop upward from the stem base, and premature senescence of the plant. In contrast, F. redolens does not cause discoloration of the vascular tissues in chickpea but does cause brown necrotic lesions in the tap root and necrosis of lateral roots. F. redolens is not easily differentiated from F. oxysporum f. sp. ciceris using morphology-based diagnosis, and the two species cause similar symptoms on chickpea; therefore, the use of molecular protocols should help to avoid misdiagnoses of Fusarium yellows in chickpea.

Fusarium Wilt Affecting Chickpea Crop

“…f Sp. ciceris (Padwick) T. Matuo & K. Satô [19][20][21]. On potato sucrose agar and potato dextrose agar and under near-UV light, the aerial mycelium is at first white and cottony, but later it may become cream or salmon in color or remain white [22].…”

“…A study conducted by Jimenez-Fernandez et al [19] revealed that infection of chickpea by F. redolens induces a disease syndrome similar to that caused by the yellowing pathotype of F. oxysporum fsp. Ciceris (Foc).…”

Evaluation of Cowpea Genotypes for Resistance to <i>Fusarium redolens</i> in Uganda

“…Leaf yellowing (chlorosis) is one of the main symptoms of F. redolens [21]. In this study, resistant plants remained relatively green thus retaining high chlorophyll in their leaves and stalks while susceptible plants turned yellow.…”

“…This could be due to infestation of mites in the second trial that might have influence the observed chlorosis. Correlation analysis of root rot severity with leaf chlorophyll content showed a highly significant (P ≤ 0.001) negative correlation thus confirming that chlorosis can be used to infer to the presence of the pathogen [21].…”

“…From farmer field observations [11] and earlier studies [21], F. redolens was observed causing seed rot leading to low germination, leaf yellowing, root rots and plant senescence in grain legumes. Similar symptoms were confirmed during screen house evaluation in this study thus corroborating the findings of [21]. To understand this relationship, this study investigated a number of symptoms in relation to infection by F. redolens.…”