AtNSE1 and AtNSE3 are required for embryo pattern formation and maintenance of cell viability during Arabidopsis embryogenesis

Abstract

Embryogenesis is an essential process during seed development in higher plants. It has previously been shown that mutation of the Arabidopsis non-SMC element genes AtNSE1 or AtNSE3 leads to early embryo abortion, and their proteins can interact with each other directly. However, the crucial regions of these proteins in this interaction and how the proteins are cytologically involved in Arabidopsis embryo development are unknown. In this study, we found that the C-terminal including the Ring-like motif of AtNSE1 can interact with the N-terminal of AtNSE3, and only the Ring-like motif is essential for binding with three α motifs of AtNSE2 (homologous to AtMMS21). Using genetic assays and by analysing molecular markers of cell fate decisions (STM, WOX5, and WOX8) in mutant nse1 and nse3 embryos, we found that AtNSE1 and AtNSE3 work non-redundantly in early embryo development, and that differentiation of the apical meristem and the hypophysis fails in the mutants, which have disrupted auxin transportation and responses. However, the upper cells of the suspensor in the mutants seem to have proper embryo cell identity. Cytological examination showed that cell death occurred from the early embryo stage, and that vacuolar programmed cell death and necrosis in the nse1 and nse3 mutant embryos led to ovule abortion. Thus, AtNSE1 and AtNSE3 are essential for maintaining cell viability and growth during early embryogenesis. Our results improve our understanding of the functions of SMC5/6 complex in early embryogenesis in Arabidopsis.

Vitamin B1 THIAMIN REQUIRING1 synthase mediates the maintenance of chloroplast function by regulating sugar and fatty acid metabolism in rice

“…The third and fourth leaves from four-leave stage seedlings of WT and the cles were used to investigate their cellular ultrastructure. Sample fixation, dehydration, and embedding were performed as previously described (Li et al, 2019). Ultrathin sections (60-70 nm) were cut using an ultramicrotome (EM UC7; Leica Microsystems, Germany), and imaged under a transmission electron microscope (JEM-1400plus; JEOL, Japan).…”

Cytological characteristics of blueberry fruit development

“…Although the mature blueberry fruit consists mostly of flesh, and seeds occupy a smaller proportion, seed development is a crucial phase in the life cycle of higher plants. It can directly impact fruit properties and is vital for plant reproduction and crop yield [ 13 ].…”