Molecular Studies on Some Important Enzymes Involved in Tuberization of an Indian Potato Solanum tuberosum L Cultivar Kufri Chipsona 1

Abstract

Potato, a Solanaceae family member, is a nutritionally rich non-grain food crop cultivated all over the world. It is a promising crop capable to fight both hunger and malnutrition. Potato occupies a distinct position only after the major cereals in terms of fulfilling nutritional requirements/consumer acceptance. Tuberization, a complex developmental morpho-physiological process, is the most sensitive phase of the potato plant life cycle. Multiple genetic, physio-biochemical and environmental factors are known to influence several successive stages of tuberization: stolon initiation and growth, tuber induction and initiation, cell growth and tuber enlargement accompanied by the accumulation of storage biomolecules namely starch and proteins. As evident in the multiple research reports/reviews, the developmental stages of tuberization are associated with the expression of multiple constitutive and organ/cell type-specific genes. Multiple complex signalling and metabolic pathways are known to be involved in this process. Phytohormone signalling, lipoxygenase (LOX) cascade and reactive oxygen species (ROS) metabolism are some examples having significant influence on the tuberization process. Most of the potato cultivars are autotetraploids and shows high levels of heterozygosity. Usually, a particular gene has multiple forms (allelic variants) which could vary with regard to their spatio-temporal nature of expression patterns, and importantly functional attributes. Considerable progress has been made at genetic, molecular and biochemical levels with regard to the process of tuberization in potato. In-depth studies at molecular and biochemical levels are still required to clearly understand this complex process. The thesis work mainly focussed on some genes in an Indian potato cultivar, Kufri Chipsona-1 (KC-1) encoding the crucial enzymes namely Gibberellin 2-oxidases (GA2oxs), Lipoxygenases (LOXs) and Ascorbate peroxidase (APXs). Since these enzymes are associated with some of the crucial metabolic pathways that