Chlorophyll retention caused by STAY-GREEN (SGR) gene mutation enhances photosynthetic efficiency and yield in soybean hybrid Z1

Abstract

To study the effect of a stay-green mutation on photosynthetic efficiency in hybrid offspring of soybean (Glycine max [L.] Merr.), the parameters of photosynthesis and chlorophyll (Chl) fluorescence were compared between a new stay-green variety Jinda Zhilv No. 1 (Z1) and one of its parents Jinda No. 74 (JD74). During leaf natural senescence, the Chl degradation attenuated in Z1. The net photosynthetic rate, stomatal conductance, and transpiration rate were consistently higher in Z1 than that in JD74 after flowering. The decreases of maximum photochemical efficiency of PSII, actual photochemical efficiency of PSII, and photochemical quenching coefficient were greater in JD74 than in Z1. Transcriptional levels of most genes involved in photosystems were much higher in Z1. All these effectively contributed to maintained photosystem stability and enhanced photosynthetic efficiency and yield in Z1. We also revealed that the STAY-GREEN gene mutation was responsible for inhibiting Chl degradation in Z1.

Keywords

• chlorophyll degradation
• chlorophyll fluorescence
• gene expression
• photosynthetic rate
• stay-green mutation