The MhLHCB15 gene interacts with interacting proteins to regulate iron deficiency tolerance in Malus halliana

Abstract Background Iron (Fe) plays a crucial role as a micronutrient in facilitating plant growth and development. Alterations in the availability of iron can trigger a response resulting in iron deficiency, ultimately affecting both plant growth and crop yield. Results A total of 33 MhLHC family members were identified in Malus halliana based on the apple genome database under Fe deficiency. The study comprehensively analyzed the physicochemical properties, gene structures, conserved motif compositions, evolutionary relationships, and chromosomal distributions of these family members. Additionally, 15 genes were selected for qRT-PCR to verify whether they responded to abiotic stress. It was demonstrated that MhLHCB15 significantly responded to Fe deficiency stress. Among them, Further investigation was conducted on the functional properties of MhLHCB15 in Arabidopsis and apple calli. Overexpression of MhLHCB15 enhanced Fe deficiency tolerance of in both Arabidopsis and apple calli, which evoked a variety of biochemical changes: transgenic Arabidopsis displayed higher photosynthetic efficiency (Tr, Gs, and Pn) and fluorescence parameters (qP, F0, Fm, and Fv/Fm) and lower Ci compared to the WT. The chlorophyll content, photosynthetic products (SS, St and SP), and enzyme activities (SOD, POD and CAT) of transgenic A. thaliana and apple calli were markedly higher compared to the WT, however, the MDA content and ROS accumulation were less than the WT. Moreover, the FCR activity of transgenic Arabidopsis and apple calli was stronger in comparison to the WT. Conclusions In summary, overexpression of the MhLHCB15 gene enhanced Arabidopsis and apple calli tolerance to Fe deficiency stress. In this study, the interaction proteins MhSGR1 and MhTHF1 of MhLHCB15 were screened, which contributes to further analyze the regulation of MhLHCB15 on Fe deficiency tolerance of M. halliana.