Wild Sugarcane - Saccharum sp. germplasm collection in the states of Punjab and Haryana, India

The Indian sub-continent harbours a great wealth of diversity of Saccharum and its related genera. Several targeted expeditions were conducted to collect the range of diversity present in Saccharum complex from diverse parts of the country. But the north western states of Punjab and Haryana were hitherto unexplored. A targeted exploration was conducted during 2016 to collect the entire range of variability present in Saccharum complex. Collections were made from a wide range of habitats and altitudes. The Saccharum spontaneum was present mostly along the river banks and river beds and showed considerable variability for morphological characteristics. S. spontaneum was distributed throughout both the states and collections could be made from all the districts and union territory of Chandigarh. A total of 104 accessions comprising of 100 Saccharum spontaneum and four Erinathus sp. have been collected. They were occurring mostly as small population except in the canal bunds where larger population was noticed. Plant height ranged from 0.46 m to 4.5 m. Variation for leaf and stem characters were observed from the collections. Statistical analysis of altitude of the collection sites with plant characters showed no significant association. Correlation analysis among plant characters showed the highest correlation coefficient between plant height and internode thickness. Clustering of Haryana, Chandigarh and Punjab Saccharum spontaneum collections through complete linkage clustering resulted in five clear clusters among the collections. Geographic distance and environmental factors including local climates interplay in the formation of the genetic structure and geographic patterns of the native S. spontaneum populations. Haryana and Punjab state were not much explored during earlier period and hence the collection would add more diversity to the germplasm maintained. In addition to the 100 S. spontaneum, four Erianthus sp. were collected during the exploration which will enrich the gene pool

Deep sequencing of suppression subtractive library identifies differentially expressed transcripts of Saccharum spontaneum exposed to salinity stress

Saccharum spontaneum, a wild relative of sugarcane, is highly tolerant to drought and salinity. The exploitation of germplasm resources for salinity tolerance is a major thrust area in India. In this study, we utilized suppression subtractive hybridization (SSH) followed by sequencing for the identification of upregulated transcripts during salinity stress in S. spontaneum clones coming from different geographical regions of India. Our sequencing of the SSH library revealed that 95% of the transformants contained inserts of size 200–1500 bp. We have identified 314 differentially expressed transcripts in the salinity-treated samples after subtraction, which were subsequently validated by quantitative real-time polymerase chain reaction. Functional annotation and pathway analysis revealed that the upregulated transcripts were a result of protein modifications, stress, and hormone signaling along with cell wall development and lignification. The prominently upregulated transcripts included UDP glucose dehydrogenase, cellulose synthase, ribulose, cellulose synthase COBRA, leucine-rich protein, NAC domain protein, pectin esterase, ABA-responsive element binding factor 1, and heat stress protein. Our results is a step forward the understanding of the molecular response of S. spontaneum under salinity stress, which will lead to the identification of genes and transcription factors as novel targets for salinity tolerance in sugarcane