ACC-Deaminase, Phosphate-Solubilizing Pseudomonas fluorescens Increase Phosphorus and Decrease Cadmium Concentration to Enhance Wheat Yield

Abstract

Phosphorus (P) fertilization of wheat at higher dose may result in grain cadmium (Cd) accumulation. This field study envisaged yield and comparative P and Cd accumulation of wheat under different P doses, i.e. 0, 45 and 90 kg P2O5 ha-1 (P0, P45 and P90, respectively) and seed inoculation with rhizobacterial strains, i.e. no Pseudomonas fluorescens (SM0), with ACC-deaminase P. fluorescens (SM1) and with phosphate-solubilizing, ACC-deaminase P. fluorescens (SM2). The soil was non-saline, alkaline clay loam, poor in organic matter and P content. Both P nutrition and rhizobacteria positively affected wheat growth, yield and nutrient concentration. Increased 1000-grain weight (TGW), yield and P concentration of wheat was noted at P90 over P0 (24-132%) and P45 (3.7-37%), and in case of SM2 (13-57%) and SM1 (5.4-34%) over SM0, and for SM2 over SM1 (1.4 to 2.4-fold). Grain-Cd concentration decreased at P90 over P0 (34%) and P45 (17%), and at P45 over P0 (21%). It decreased over SM0 at SM2 (22%) and SM1 (8%), and over SM1 at SM2 (2.7-fold). Straw-Cd concentration decreased at P90 over P0 (25%) and P45 (18%), and over P0 at P45 (8%). It decreased over SM0 at SM2 (18%) but increased at SM1 (9%). At all P levels, SM2 was more effective over SM1 or SM0. TGW and straw-P increased for P90 interacting with SM2 over SM0 (8.6 and 29%) and SM1 (6 and 14%), and for SM1 over SM0 (2.5 and 13%). Grain- and straw-Cd decreased due to interaction of P90 with SM2 (30 and 23%) or SM1 (6 and 7%) over SM0, and for SM1 over SM0 (26% and 17%). We conclude that adequate P nutrition and seed inoculation with ACC-deaminase, phosphate-solubilizing Pseudomonas fluorescens increase growth and yield of wheat due to its increased P and decreased Cd concentration.