Anjly Pancholy

Assessment of Genetic Diversity in Trigonella foenum-graecum Based on Nuclear Ribosomal DNA, Internal Transcribed Spacer and RAPD Analysis

Fenugreek (Trigonella foenum-graecum) is receiving global attention due to rare medicinal properties of significance to human health. Gene banks possess scanty germplasm and very little background information regarding its genetic variability that has hampered its improvement. We investigated the extent of variability among 17 Indian varieties of fenugreek using phenotypic and genetic markers. Multilocus genotyping by ten random amplified polymorphic DNA (RAPD) primers detected an average of intraspecific variations amounting to 64.7% polymorphism in banding patterns. Analysis of molecular variance indicated that a greater proportion of total genetic variation exists within population (91%) rather than among populations. Higher values of Nei’s gene diversity (h) and Shannon Information Index (i) and genetic distance analysis validate higher genetic diversity among Indian fenugreek varieties. SNPs at 14 sites of rDNA region revealed further lineages of distinct varieties with main RAPD clusters. The representative sequences of each subgroup and all distinct varieties have been submitted to NCBI database and assigned Gen Accession numbers HM 176640–176649. The measures of relative genetic distances among varieties of fenugreek did not completely correlate with the geographical distances of places of their development. The homogeneous phenotypic markers proved insufficient in exhibiting genetic divergence among fenugreek varieties studied. Eventually, the knowledge of their genetic relationships, DNA bar coding and phylogenies might contribute for the designing of intraspecific crosses between cultivars of this fenugreek collection with potential interest in seed spices breeding programme.

Biodiversity in wood-decay macro-fungi associated with declining arid zone trees of India as revealed by nuclear rDNA analysis

Wood-decay macro-fungi have been reported to be a major cause of decline of arid zone trees in the genera Acacia, Prosopis, Ziziphus and Azadirachta; the identity of these fungi, however, has not been confirmed in the state of Rajasthan in northwestern India. Direct sequencing of PCR amplified ITS regions of rDNA facilitated molecular identification of 26 isolates into species in eight genera (Ganoderma, Inonotus, Phellinus, Ceriporia, Schizophyllum, Phanerochaete, Pleurotus, Leucoagaricus) and one incompletely characterized Basidiomycota species. In addition to intra-specific phenotypic variations in basidiocarp morphology, Single Nucleotide Polymorphisms (SNPs) were recorded among isolates of P. pulmonarius, S. commune, G. lucidum and Ganoderma species. Both SNPs and insertions/deletions (INDELS) were recorded amongst Inonotus species. A phylogram based on multiple sequence alignment delineated all isolates into separate intra-specific subgroups along with their GenBank reference sequences with high bootstrap values. Phellinus repandus, L. meleagris, C. lacerata and three Inonotus species (I. rickii, I. patouillardii, and I. porrectus) reported herein are new fungal records from India.

Role of Root Nodule Bacteria in Improving Soil Fertility and Growth Attributes of Leguminous Plants Under Arid and Semiarid Environments

The nitrogen fixation is a key factor in low-input agricultural systems to sustain long-term soil fertility. Plant–bacteria interactions in the rhizosphere are the determinants of plant health and soil fertility. The climatic conditions of arid and semiarid regions are often characterized by hot, dry summers, subhumid monsoon, and cold dry winter. The climatic conditions in this region restrict the buildup of soil organic matter and soils are generally deficient in nitrogen. Knowledge of rhizobial diversity from arid and semiarid areas is essential to improve their nutrient-poor fertility status. Soils of these regions often suffer from moisture stress, salinity, unfavorable pH, nutrient deficiency, mineral toxicity, temperature extremes, plant diseases, trace element deficiencies, etc., which inhibit nodulation and impose limitations on the vigor of the host legume. The tolerance to high levels of salinity and the survival and persistence in harsh desert conditions make these rhizobia highly valuable inocula to improve productivity of the leguminous plants cultivated under extreme environments. This functional diversity and tolerance to extreme environments displayed by efficient rhizobial isolates alone or co-inoculation with PGPR can be effectively utilized for improving legume crop production and productivity in arid and semiarid regions.