Characterization of sucrose non-fermenting-1 (SNF1) homologue gene in Fusarium udum WSP-V2 and its regulation by the biocontrol agent Pseudomonas fluorescens OKC.

Sucrose non-fermenting 1 (SNF1) is a protein kinase and plays an important role in the energy homeostasis of glucose repressible gene transcription. It derepresses glucose repressed genes and associated with pathogenesis and production of cell wall degrading enzymes in fungal species. In the present study, we identified and characterized SNF1 homologue FuSNF1 in the F. udum strain WSP-V2. Transcript analysis of FuSNF1 along with the MAP kinases and some cell wall degrading enzyme (CWDE) genes of F. udum during interaction with pigeonpea revealed that most MAP kinases and CWDE genes was positively correlated with the FuSNF1 gene. Interestingly, transcript accumulation of all these genes was lowered when pigeonpea seeds were bioprimed with a PGPR strain Pseudomonas fluorescens OKC. Transcript accumulation of FuSNF1 was observed from the day of inoculation and reached maximum level on day 7 in OKC non-bioprimed plants. However, transcript accumulation was low (1.5 fold) in F. udum inoculated with pigeonpea plants bioprimed with OKC. Transcript accumulation patterns of the F. udum MAP Kinases genes and CWDE genes also showed a similar trend and their transcript accumulation was lowered in the OKC bioprimed treatment. The results thus indicate a prime role of FuSNF1 in regulating pathogenicity and virulence of F. udum. The results further emphasize the importance of application of effective PGPR strains in regulating virulence of F. udum. In silico analysis of the SNF1 reference proteins from different fungal species showed that their homologue FuSNF1 is likely to be thermostable and acidic in nature.

Trichoderma mediate early and enhanced lignifications in chickpea during Fusarium oxysporum f. sp. ciceris infection.

Lignifications in secondary cell walls play a significant role in defense mechanisms of plants against the invading pathogens. In the present study, we investigated Trichoderma strain specific lignifications in chickpea plants pre-treated with 10 potential Trichoderma strains and subsequently challenged with the wilt pathogen Fusarium oxysporum f. sp. ciceris (Foc). Trichoderma-induced lignifications in chickpea were observed through histochemical staining and expression of some genes of the lignin biosynthetic pathway. Lignifications were observed in transverse sections of shoots near the soil line through histochemical staining and expression pattern of the target genes was observed in root tissues through semi quantitative RT-PCR at different time intervals after inoculation of F. oxysporum f. sp. ciceris. Lignin deposition and expression pattern of the target genes were variable in each treatment. Lignifications were enhanced in all 10 Trichoderma strain treated and F. oxysporum f. sp. ciceris challenged chickpea plants. However, four Trichoderma strains viz., T-42, MV-41, DFL, and RO, triggered significantly high lignifications compared to the other six strains. Time course studies showed that effective Trichoderma isolates induced lignifications very early compared to the other strains and the process of lignifications nearly completes within 6 days of pathogen challenge. Thus, from the results it can be concluded that effective Trichoderma strains trigger lignifications very early in chickpea under Foc challenge and provide better protection to chickpea plants.

Compatible Rhizosphere-Competent Microbial Consortium Adds Value to the Nutritional Quality in Edible Parts of Chickpea.

Chickpea is used as a high-energy and protein source in diets of humans and livestock. Moreover, chickpea straw can be used as alternative of forage in ruminant diets. The present study evaluates the effect of beneficial microbial inoculation on enhancing the nutritional values in edible parts of chickpea. Two rhizosphere-competent compatible microbes (Pseudomonas fluorescens OKC and Trichoderma asperellum T42) were selected and applied to seeds either individually or in consortium before sowing. Chickpea seeds treated with the microbes showed enhanced plant growth [88.93% shoot length at 60 days after sowing (DAS)] and biomass accumulation (21.37% at 120 DAS). Notably, the uptake of mineral nutrients, viz., N (90.27, 91.45, and 142.64%), P (14.13, 58.73, and 56.84%), K (20.5, 9.23, and 35.98%), Na (91.98, 101.66, and 36.46%), Ca (16.61, 29.46, and 16%), and organic carbon (28.54, 17.09, and 18.54%), was found in the seed, foliage, and pericarp of the chickpea plants, respectively. Additionally, nutritional quality, viz., total phenolic (59.7, 2.8, and 17.25%), protein (9.78, 18.53, and 7.68%), carbohydrate content (26.22, 30.21, and 26.63%), total flavonoid content (3.11, 9.15, and 7.81%), and reducing power (112.98, 75.42, and 111.75%), was also found in the seed, foliage, and pericarp of the chickpea plants. Most importantly, the microbial-consortium-treated plants showed the maximum increase of nutrient accumulation and enhancement in nutritional quality in all edible parts of chickpea. Nutritional partitioning in different edible parts of chickpea was also evident in the microbial treatments compared to their uninoculated ones. The results thus clearly demonstrated microbe-mediated enhancement in the dietary value of the edible parts of chickpea because seeds are consumed by humans, whereas pericarp and foliage (straw) are used as an alternative of forage and roughage in ruminant diets.