Johri, A. K. | bioRxiv Science

bioRxiv2021

The Sugar Porter gene family of Piriformospora indica: Nomenclature, Transcript Profiling and Characterization

Piriformospora indica is one of the prominent mutualistic root endophyte known to overcome phosphate and nitrogen limitation in a wide variety of plant species, reciprocally takes up carbohydrates for its survival and growth. A total of nineteen potential hexose transporters have been identified from P. indica genome, that may contributes to its potential of carbohydrate assimilation from host plant. Phylogenetic analysis assembles it in 10 groups within 3 clusters. To ease the study, systematic nomenclature were provided to 19 putative hexose transporters as "PiST1-PiST19" in accordance to their appearance on the supercontigs genome sequence of P. indica. The protein length ranges from 487 to 608 amino acids. Out of 19 putative hexose transporters, 9 have been predicted to contain 12 transmembrane domains (PiST1, PiST2, PiST5, PiST6, PiST9, PiST10, PiST11, PiST12 and PiST17), along with MFS family and Sugar porter subfamily motif. Therefore, transcripts were detected for these 9 genes. During colonization, three P. indica genes PiST1, PiST5 and PiST9 have shown induction as compared to axenic culture. Similarly during phosphate starvation, revealed PiST12 to be strongly enhanced. Carbon starvation study in liquid axenic culture resulted in induction of 4 genes, PiST6, PiST9, PiST12 and PiST17. We found co-relation in the expression pattern of PiPT and PiST12 during phosphate starvation. In silico analysis revealed the presence of functional conserved fucose permease (FucP) domain, involved in fructose transport. Phylogenetic analysis revealed that PiST12 groups closely with basidiomycetes hexose transporters. Further, functional complementation of {Delta}hxt null mutant revealed, PiST12 is able to complement growth on fructose and galactose but negligible on glucose.

plant biology↗

bioRxiv2020

Role of Sulphate Transporter (PiSulT) of Endophytic Fungus Serendipita indica in Plant Growth and Development

Sulfur is an important macronutrient required for the growth, development of plants and is a key component of many metabolic pathways. We have functionally characterized a high-affinity sulphate transporter (PiSulT) from an endophytic fungus Serendipita indica. The PiSulT belongs to the major facilitator superfamily (MFS) of membrane transporter. The PiSulT functionally complements the yeast sulphate transporter mutant HK14. PiSulT is a high-affinity sulphate transporter, having Km 15M. We found enhanced expression of PiSulT in external fungal hyphae which helps the fungus in the acquisition of sulphate from the soil. When knockdown (KD)-PiSulT-P.indica colonized with the plant, it results in an 8-fold reduction in the transfer of sulphate to the colonized plants as compared to the plants colonized with the WT S. indica, which suggests that PiSulT is playing a role in sulphate transfer from soil to host plant. Further, plants colonized with the WT S. indica were found to be healthy in comparison to the plants colonized with the KD-PiSulT-P.indica. Additionally, S. indica colonization provides a positive effect on total sulfur content and on plant metabolites like sulfate ions and glutathione, particularly under low sulphate condition. We observed that the expression of sulfur assimilation pathway genes of S. indica and plant is dependent on the availability of sulphate and on the colonization with the plant. Our study highlights the importance of PiSulT in the improvement of sulfur nutrition of host plant particularly under low sulphate condition and in plant growth development. This study will open new vistas to use S. indica as a bio-fertilizer in the sulphate deficient field to improve crop production. One-Sentence SummaryHigh-affinity sulphate transporter of Serendipita indica (PiSulT) transfer sulphate from soil to plant under low sulphate condition and improve plant growth and development.

microbiology↗