Integrating Biofertilizers with Organic Fertilizers Enhances Photosynthetic Efficiency and Upregulates Chlorophyll-Related Gene Expression in Rice

Abstract

Biofertilizers offer a sustainable method for improving rice growth and productivity, yet their effects on the interaction between plant growth, photosynthetic activity, and gene expression remain under-researched. This study examines how biofertilizer influences rice physiology, focusing on photosynthetic regulation and expression of chlorophyll-related genes. Eight fertilizer treatments were applied: control (CNT), biofertilizer (BF), deactivated biofertilizer (DABF), rice straw (RS), rice straw with biofertilizer (RS+BF), organic fertilizer (OF), organic fertilizer with biofertilizer (OF+BF), and inorganic fertilizer (IOF). Plant height, tiller number, SPAD, NDVI, chlorophyll content, and photosynthesis rates were measured, while gene expression analysis was conducted using RT-qPCR. The OF+BF treatment produced the most significant results, leading to a 31% increase in plant height, a 135% increase in tiller number, and a 42% increase in chlorophyll content (SPAD values) compared to the control. Additionally, OF+BF enhanced photosynthetic efficiency by 74%, with the highest net photosynthetic rate of 48.23 μmol CO2 m−2 s−1. Gene expression analysis revealed that OF+BF upregulated key photosynthesis-related genes, such as OsChlD and OsCHLM, showing a 70% and 90% increase in expression. These findings highlight the potential of integrating biofertilizers with organic fertilizers to sustainably boost rice growth and productivity, contributing to global food security and climate change mitigation.