Rhizobacteria Inoculation and Caffeic Acid Alleviated Drought Stress in Lentil Plants

Muhammad Zafar-Ul-Hye,Rahul Datta,Mohammad Javed Ansari,Subhan Danish,Muhammad Naeem Akbar,Muqarrab Ali,Shah Fahad,Atiqa Zahid,Mazhar Abbas,Abdallah M Elgorban,Yasir Iftikhar

doi:10.3390/su13179603

Abstract

Lentil (Lens culinaris Medik) is an important component of the human diet due to its high mineral and protein contents. Abiotic stresses, i.e., drought, decreases plant growth and yield. Drought causes the synthesis of reactive oxygen species, which decrease a plant’s starch contents and growth. However, ACC-deaminase (1-aminocyclopropane-1-carboxylate deaminase) producing rhizobacteria can alleviate drought stress by decreasing ethylene levels. On the other hand, caffeic acid (CA) can also positively affect cell expansion and turgor pressure maintenance under drought stress. Therefore, the current study was planned with an aim to assess the effect of CA (0, 20, 50 and 100 ppm) and ACC-deaminase rhizobacteria (Lysinibacillus fusiform, Bacillus amyloliquefaciens) on lentils under drought stress. The combined application of CA and ACC-deaminase containing rhizobacteria significantly improved plant height (55%), number of pods per plant (51%), 1000-grain weight (45%), nitrogen concentration (56%), phosphorus concentration (19%), potassium concentration (21%), chlorophyll (54%), relative water contents RWC (60%) and protein contents (55%). A significant decrease in electrolyte leakage (30%), proline contents (44%), and hydrogen peroxide contents (54%), along with an improvement in cell membrane stability (34% over control) validated the combined use of CA and rhizobacteria. In conclusion, co-application of CA (20 ppm) and ACC-deaminase producing rhizobacteria can significantly improve plant growth and yield for farmers under drought stress. More investigations are suggested at the field level to select the best rhizobacteria and CA level for lentils under drought.

Highlights

Lentil (Lens culinaris Medik) is an important Rabi crop that primarily originated from southwest Asia and the Mediterranean
The data revealed that ACC-deaminase containing rhizobacteria (Lysinibacillus fusiform and Bacillus amyloliquefaciens) significantly improved growth parameters, plant height, number of pods per plant, 1000-grain weight, and chlorophyll contents of the lentil crop under drought stress as compared to the control
A combined caffeic acid (CA) application at 20 ppm and Bacillus amyloliquefaciens significantly improved plant height up to 55% compared to the control under drought conditions

Summary

Introduction

Lentil (Lens culinaris Medik) is an important Rabi crop that primarily originated from southwest Asia and the Mediterranean. Lentil is a rich source of proteins, minerals (zinc, iron, cobalt and calcium), carbohydrates, and vitamins (lysine and arginine). Lentil ranks sixth among major pulses in terms of productivity [1]. 75% of world lentil production annually [2]. North America are the major producers of lentils globally. Root nodules of lentils play an important role in improving soil fertility through biological nitrogen fixation [3]

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Discussion

Conclusion