Variations in proline accumulation and relative water content under water stress characterize bean mutant lines (P. vulgaris L.)

Veselina Masheva, Velichka Spasova-Apostolva, Sibel Aziz and Nasya Tomlekova

Abstract: Drought stress linked with climate change is one of the major reasons limiting the productivity of crop species. This investigation was intended to characterize 19 bean mutant (Phaseolus vulgaris L.) genotypes for water-deficit tolerance, by determining their relative water content and proline accumulation. The drought stress was simulated by Polyethylene Glycol (PEG6000). The response of the two populations with initial genotypes – variety Evros and variety Mastilen 11b were evaluated in pots arranged in a three-plot design. The pots were placed in a greenhouse with full sunlight. The plants were watered using liquid ½ Murashige and Skoog (MS) nutrient solution every 2 days (50 mL per pot). After the plants have three trifoliate leaves(± 14 days after planting) the solution was combined with PEG (20% PEG equivalent to – 1,2 Mpa osmotic potential) solution treatment and the volumes were increased up to 100 mL. The control plants were watered with a ½ MS nutrient solution without PEG. During the treatment with PEG changes of RWC % in leaves and roots were observed. Drought stress resulted in a significant reduction in fresh and dry leaf and root weights and relative water content (RWC %). Proline content of the studied mutant lines increased when plants were subjected to water deficit. The results indicated that M3 mutant lines (variant 9, variant 16, and variant 20) exhibited the best drought tolerance and are good candidates for further evaluation to release mutant varieties or to be used as donor parents in a bean crop improvement program towards drought tolerance.

Keywords: mutant lines (P. vulgaris L.); proline; relative water content; water stress

Date published: 2022-06-15