Auxin guides germ cell specification in Arabidopsis anthers

Abstract

Germ cells (GCs) transmit genetic information from one generation to the next. Unlike animal GCs, plant GCs are induced post-embryonically, forming locally from somatic cells. This induction is coordinated with organogenesis and might be guided by positional cues. In angiosperms, male GCs initiate from the internal layers at the four corners of the anther primordia and are gradually enclosed by parietal cell (PC) layers, leading to a concentric GC-PC pattern. However, the underlying mechanism of GC initiation and GC-PC pattern formation is unclear. Auxin affects pattern formation3 and anther development. However, whether GC formation involves auxin remains unknown. We report that the auxin distribution in pre-meiotic anthers parallels GC initiation, forming a centripetal gradient between the outer primordial cells and the inner GCs. The auxin biosynthesis genes TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1 (TAA1) and TRYPTOPHAN AMINOTRANSFERASE RELATED 2 (TAR2) are responsible for this patterning and essential for GC specification. SPOROCYTELESS/NOZZLE (SPL/NZZ, a determinant for GC specification) mediates the effect of auxin on GC specification, modulates auxin homeostasis, and maintains centripetal auxin patterning. Our results reveal that auxin is a key factor guiding GC specification in Arabidopsis anthers.

OsMADS58 stabilizes gene regulatory circuits during rice stamen development

“…Tapetum differentiation is regulated by many genes in rice (Zhang and Yang, 2014;Chen et al, 2018). Notably, mutants with aberrant MMC differentiation also fail to differentiate the tapetum properly, similar to that found in Arabidopsis (Zhao et al, 2002;Hord et al, 2008;Zhao et al, 2017;Zheng et al, 2021). It has therefore been suggested that tapetum differentiation is dependent on MMC differentiation (Tan et al, 2012;Zhang and Yang, 2014).…”

The GA–DELLA–OsMS188 module controls male reproductive development in rice

“…4; Tables S6, S7). Auxin is a key factor guiding the germ cell specification in Arabidopsis anthers (Zheng et al ., 2021). Previous studies have shown that DELLA proteins can interact directly with hormone‐related proteins, such as PIF4, ARRs, MYC3 and JAZ1, in Arabidopsis (Kwon & Paek, 2016; Bao et al ., 2020).…”

Specification of female germline by microRNA orchestrated auxin signaling in Arabidopsis

“…SPL/ NZZ was suggested to be involved in auxin homeostasis 49 . A recent study showed that auxin distribution is associated with differentiation of the male germ cell PMC (pollen mother cell) 50 . Mutations in auxin biosynthesis genes TAA1 (TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1) and TAR2 (TRYPTOPHAN AMINOTRANSFERASE RELA-TED 2) impair the PMC formation, whereas ectopic expression of SPL/NZZ partially rescues the PMC specification.…”