In-vivo and in-vitro Screening of Drought Tolerance and Molecular Characterization of Sugarcane (Saccharum Officinarum L.) Varieties

Abstract

Sugarcane, a vital agricultural commodity known for its unique ability to accumulate sucrose in its stalks, holds a prominent position as the world's primary crop in terms of production quantity. The global challenge of inadequate disease-free high-quality planting material has a detrimental impact on sugarcane production. To address this issue, the present study focused on optimizing hormonal requirements to enhance rapid and prolific shoot multiplication in two sugarcane genotypes, Co15023 and Cos 13235, aiming to produce superior planting material. The study commenced with the meticulous surface sterilization of explants, employing a series of treatments including 0.1% bavistin for 10 minutes, followed by 0.1% HgCl₂ for 5 minutes, 6% laboline for 10 minutes, and 70% EtOH for 1 minute. Subsequently, the researchers explored media formulations enriched with various growth regulators such as BAP and Kn. For genotype Co 15023, the most favorable shoot multiplication and growth occurred in media T11 (M S Basal + 0.5 BAP mg/L + 0.5 Kinetin mg/L + 30g Sucrose), while genotype Cos 13235 exhibited optimal response in media T11 (M S Basal + 0.5 BAP mg/L + 0.5 Kinetin mg/L + 30g Sucrose). This strategic approach holds significant promise for enhancing sugarcane planting material production. Shifting focus, the study addressed the susceptibility of sugarcane to abiotic stresses, particularly drought, which hampers production due to the crop's extended life cycle. The investigation encompassed a screening of fifteen sugarcane genotypes under semi-arid conditions in India. Physiological, biochemical, and antioxidant responses were evaluated at two water deficit levels. Notably, genotype Co 98014 exhibited the least alteration in various parameters such as RWC, MSI, total chlorophyll content activity, H₂O₂ content, and lipid peroxidation, and demonstrated higher antioxidant enzyme activity and significant proline accumulation. Given these findings, the study delved into gene expression patterns of selected tolerant (Co 15023 and Cos 13235) genotypes. Differential expression analysis of four genes, including SOD, DREB 1A, DREB 2A, and LEA, highlighted significantly higher expression of SOD, and DREB in the tolerant genotypes. These findings suggest the potential role of these genes in drought tolerance mechanisms. In conclusion, this study offers valuable insights into optimizing hormonal conditions for enhanced sugarcane shoot multiplication and provides molecular understanding of drought responses and gene expression patterns in sugarcane genotypes. These findings have significant implications for improving sugarcane production and resilience under challenging environmental conditions.