Arabidopsis Novel Microgametophyte Defective Mutant 1 Is Required for Pollen Viability via Influencing Intine Development in Arabidopsis

Abstract

The pollen intine layer is necessary for male fertility in flowering plants. However, the mechanisms behind the developmental regulation of intine formation still remain largely unknown. Here, we identified a positive regulator, Arabidopsis novel microgametophyte defective mutant 1 (AtNMDM1), which influences male fertility by regulating intine formation. The AtNMDM1, encoding a pollen nuclei-localized protein, was highly expressed in the pollens at the late anther stages, 10–12. Both the mutations and the knock-down of AtNMDM1 resulted in pollen defects and significantly lowered the seed-setting rates. Genetic transmission analysis indicated that AtNMDM1 is a microgametophyte lethal gene. Calcofluor white staining revealed that abnormal cellulose distribution was present in the aborted pollen. Ultrastructural analyses showed that the abnormal intine rather than the exine led to pollen abortion. We further found, using transcriptome analysis, that cell wall modification was the most highly enriched gene ontology (GO) term used in the category of biological processes. Notably, two categories of genes, Arabinogalactan proteins (AGPs) and pectin methylesterases (PMEs) were greatly reduced, which were associated with pollen intine formation. In addition, we also identified another regulator, AtNMDM2, which interacted with AtNMDM1 in the pollen nuclei. Taken together, we identified a novel regulator, AtNMDM1 that affected cellulose distribution in the intine by regulating intine-related gene expression; furthermore, these results provide insights into the molecular mechanisms of pollen intine development.

Construction of Genetic Map and QTL Mapping for Seed Size and Quality Traits in Soybean (Glycine max L.)

“…Glyma.16g129200 ( AT2G17990.1 ) was detected to be related to the function of calcium-dependent protein kinase 1 adaptor protein involved in vacuolar transport and lytic vacuole biogenesis [ 46 ]. Glyma.06g155900 ( AT5G09250.1 ) was detected to be related to the function of ssDNA-binding transcriptional regulator [ 47 ]. Glyma.06g156000 ( AT5G09230.7 ) was detected to be related to the function of Arabidopsis thaliana sirtuin 2 (SRT2) [ 48 ].…”

The transcription factors and pathways underpinning male reproductive development in Arabidopsis

“…During stage 10, intine development also starts, appearing between the plasma membrane and the nexine; here, only the microspores are involved. The NOVEL MICROGAMETOPHYTE DEFECTIVE MUTANT 1 (NMDM1) putative transcription co-activator, regulates intine development by regulating the expression of Arabidogalactin proteins (AGPs) and pectin methylesterases (PMEs) ( Mi et al., 2022 ). Concurrently, the numerous vacuoles in the microspores fuse into a large vacuole, which leads to the migration of the nucleus to one side of the cell, creating a polarized microspore.…”

High‐temperature stress in crops: male sterility, yield loss and potential remedy approaches

“…(2022a) found that the gene GhNSP has a role in nexine and spine formation because this gene encodes polygalacturonase protein that is expressed in the tapetum layer. Furthermore, during pollen development, the gene AtNMDM1 encodes a pollen nucleus localized protein and mutation in AtNMDM1 affects the intine layer which leads to abnormal pollen development (Mi et al ., 2022). In further confirmation, they produced Ghnsp and Atnmd1 ‐mutant plants, which were male sterile plants having disrupted pollen grains.…”