Plant growth-promoting rhizobacteria alleviate drought-stress in upland rice

  1. Niedja Bezerra Costa
  2. Geovanni de Oliveira Pinheiro Filho
  3. Gustavo de Andrade Bezerra
  4. Maria Rita da Silva Andrade Leonel
  5. Moemy Gomes de Moraes
  6. Marta Cristina Corsi de Filippi
  7. Rahul A. Bhosale
  8. Adriano Pereira Castro
  9. Anna Cristina Lanna
Read the full article

Listed in

This article is not in any list yet, why not save it to one of your lists.
Log in to save this article

Abstract

Drought poses a substantial risk to global agriculture and food security. Plant growth-promoting rhizobacteria (PGPR) offer a promising biotechnological alternative to enhance crop resilience to drought. This study investigated the morphophysiological and agronomic responses of Samambaia Branco, a drought-sensitive upland rice landrace, inoculated with Bacillus toyonensis (BRM 32110), Burholderia sp. (BRM 32111), and Serratia marcescens (BRM 63523), under drought stress in a phenotyping platform. Drought significantly impaired overall crop performance, reducing grain yield by 27.7% and increasing spikelet sterility up to 18.4% in non-inoculated plants. However, PGPR-inoculated plants underwent robust belowground architectural restructuring, showing average increase in root length (29.4%), surface area (34.1%), volume (36.6%) and diameter (8.7%). This enhanced root system provided a mechanistic basis for superior water status. PGPR-inoculated plants sustained higher leaf water potential under drought stress (-0.67 MPa on average) than non-inoculated plants (-1.3 MPa). Hydraulic preservation was coupled with a profound shift in non-structural carbohydrate partitioning, characterized by depletion of starch reserves (26.5%) and total soluble carbohydrates (16.7%), alongside accumulation of low-molecular-weight compatible solutes (glucose, fructose, and sucrose) osmotic adjustment. During drought and recovery, PGPR-inoculated plants, particularly BRM 32110 and BRM 63523, optimized the tradeoff between carbon gain and transpirational loss, achieving a 12.4% increase in water use efficiency and partially lowering the physiological threshold for stomatal reopening. Multivariate principal component analysis confirmed clear treatments separation, highlighting distinct microbe-mediated metabolic pathways for drought tolerance. Overall, bioagent-based technologies can bolster the climate resilience of drought-sensitive landraces, improving crop performance.

Article activity feed

  1. Version published to 10.21203/rs.3.rs-10668018/v1 on Research Square