Proline, Total Antioxidant Capacity, and OsP5CS Gene Activity in Radical and Plumule of Rice are Efficient Drought Tolerance Indicator Traits

Muhammad Abu Bakar Saddique,Babar Farid,Rao Muhammad Ikram,Muhammad Saeed Ahmad,Zulfiqar Ali,Muhammad Ali Sher,Vera Popovic

doi:10.1155/2020/8862792

Abstract

The success of a plant breeding program is linked with the rapid screening of crop germplasm. In the following study, the germination stage of rice seeds has been examined for the rapid screening of drought-tolerant genotypes. The rice genotypes (10 drought tolerant, 5 moderately drought tolerant, and 5 drought susceptible) were sown in Petri dishes under control and osmotic stress of 15% PEG6000. Data were recorded after four days of sowing for the osmotic stress-induced change in imbibition rate, speed of germination, radical and plumule length, radical and plumule total fresh and dry weight, proline contents, total antioxidant capacity, and malondialdehyde level in radical and plumule of seeds. Moreover, the change in expression of OsP5CS gene was also recorded in one of each drought tolerant, moderately drought tolerant, and drought susceptible genotypes. Under osmotic stress, the level of proline, total antioxidant capacity, and the expression of OsP5CS were increased in drought-tolerant genotypes as compared to moderately drought tolerant and drought susceptible genotypes. While, the change in imbibition rate, speed of germination, radical and plumule length, and fresh and dry weight were not symmetrical in drought tolerant, moderately drought tolerant, and drought susceptible genotypes. In short, the symmetrical change in proline, total antioxidant capacity, and expression of OsP5CS gene within radical and plumule of drought tolerant, moderately drought tolerant, and drought susceptible genotypes can help rapid screening of drought-tolerant rice genotypes.

Highlights

In the near future, water shortage will prevail, and it is projected that by 2025, almost 15 million hectares of the land will suffer physical water scarcity and 22 million hectares of economic water scarcity. e web of impacts becomes so extensive that it will be difficult to determine accurate financial estimates of damages
Plant Material and Growing Conditions. e 20 droughtresponsive genotypes (10 drought tolerant, five moderately drought tolerant (MDT), and five drought susceptible (DS)) were used in this study (Table 1). ese 20 genotypes were selected from the screening of 606 rice accessions. e drought responsiveness of these 20 genotypes was proved both at seedling and maturity stages (Figure S2). e seeds of each genotype were sown between filter papers placed in Petri dishes. e experiment was conducted at the lab bench (28°C) following the factorial under a complete randomized design
Imbibition Rate and Speed of Germination. e IR and speed of germination (SG) were significantly decreased under osmotic stress (p ≤ 0.01, Table S2)

Summary

Introduction

Water shortage will prevail, and it is projected that by 2025, almost 15 million hectares of the land will suffer physical water scarcity and 22 million hectares of economic water scarcity. e web of impacts becomes so extensive that it will be difficult to determine accurate financial estimates of damages. E genotypes were evaluated based on the drought-induced change in the imbibition rate after 24 h and 48 h (IR mg/g), the speed of germination (SG), radical length (cm), plumule length (cm), radical and plumule total fresh weight (g), radical and plumule total dry weight, proline level (ppm), total antioxidant capacity (TAC) (nm), MDA contents (nmol/ml), and expression of OsP5CS gene.

Results

Conclusion