Insight into the composition and differentiation of endophytic microbial communities in kernels via 368 maize transcriptomes

Kernels are important reproductive organs in maize, yet there is a lack of systematic investigation on the differences in the composition of endophytic microorganisms in plants from a population perspective.

We aimed to elucidate the composition of endophytic microorganisms in developing maize kernels, emphasizing differences among various inbred lines.

The transcriptomic data of 368 maize inbred lines were used to explore the composition and diversity of endophytic microorganisms.

The findings revealed a higher abundance of fungi than bacteria in developing maize kernels, followed by protozoa, while viruses were less abundant. There were significant differences in the composition and relative abundance of endophytic microorganisms among different maize lines. Diversity analysis revealed overall similarity in the community composition structure between tropical/subtropical (TST) and temperate (NSS) maize germplasm with apparent variations in community richness and abundance. The endophytic microorganisms network in the kernels from TST genotypes exhibited higher connectivity and stability compared to NSS kernels. Bacteria dominated the highly connected species in the networks, and different core species showed microbial phylum specificity. Some low-abundance species acted as core species, contributing to network stability. Beneficial bacteria were predominant in the core species of networks in TST kernels, while pathogenic bacteria were more abundant in the core species of networks in NSS kernels.

Tropical maize germplasm may have advantages in resisting the invasion of pathogenic microorganisms, providing excellent genetic resources for disease-resistant breeding.