Biotechnological approaches for development of blight resistance in selected Indian potato cultivar(s)

Abstract

Early blight and late blight are two major diseases of potato caused by fungus Alternaria solani and oomycete Phytophthora infestans respectively. These diseases are known for huge crop loss throughout the world. Most reliable approaches for reduction of yield losses caused by these diseases include genetic manipulations and pathogen-derived resistance strategies. Thus, the present study was focussed to transform a susceptible Indian potato cultivar (cv.) ‘Kufri Chipsona 1’ with a pathogenesis related gene that could potentially confer resistance to late blight and early blight in Indian potato cultivars.

As the development of an efficient regeneration system is a pre-requisite for the success of genetic manipulations, thus, shoot organogenesis and somatic embryogenesis protocols for Indian potato cultivar(s) were established using leaf and internodal explants. In the study, it was established that the regeneration frequency was influenced by certain factors, namely, plant growth regulators, medium pH, gelling agents, medium strength, sucrose concentration and heat shock treatment. It was observed that maximum leaf and internodal explants induced shoot organogenesis on Murashige and Skoog (MS) medium supplemented with 10 µM AgNO3, 10 µM BA and 15 µM GA3. This optimized medium combination was found to be effective in tested eight important Indian potato cultivars namely ‘Kufri Pukhraj’, ‘Kufri Chipsona 1’, ‘Kufri Chipsona 2’,‘KufriJyoti’, ‘Kufri Surya’, ‘Kufri Chandramukhi’, ‘Kufri Khyati’ and ‘Desiree’. Initially, attempts were made to induce somatic embryos from all the above mentioned eight cultivars but the success was achieved only in cv. ‘Kufri Chipsona 2’ on MS medium supplemented with 10 µM AgNO3, 1 µM BA and 2.5 µM GA3. Histological observations revealed development of somatic embryos directly from the epidermis of leaf explants and cut ends of internodal segments. To best of our knowledge, this is the first study reporting direct somatic embryogenesis in potato.