Kulichová Katarína, Pieters Janto, Kumar Vinod, Honys David, Hafidh Said
Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia.
Department of Plant Experimental Biology, Faculty of Science, Charles University, Prague, Czechia.
Front Plant Sci. 2022 Mar 8;13:767339. doi: 10.3389/fpls.2022.767339. eCollection 2022.
Proplastids are essential precursors for multi-fate plastid biogenesis, including chloroplast differentiation, a powerhouse for photosynthesis in plants. Arabidopsis ankyrin repeat protein (AKRP, AT5G66055) is a plastid-localized protein with a putative function in plastid differentiation and morphogenesis. Loss of function of leads to embryo developmental arrest. Whether AKRP is critical pre-fertilization has remained unresolved. Here, using reverse genetics, we report a new allele, , that exhibited a reduced frequency of mutant embryos (<13%) compared to previously reported alleles. affected both male and female gametophytes resulting in reduced viability, incompetence in pollen tube attraction, altered gametic cell fate, and embryo arrest that were depleted of chlorophyll. AKRP is widely expressed, and the AKRP-GFP fusion localized to plastids of both gametophytes, in isolated chloroplast and co-localized with a plastid marker in pollen and pollen tubes. Cell-type-specific complementation of hinted at the developmental timing at which AKRP might play an essential role. Our findings provide a plausible insight into the crucial role of AKRP in the differentiation of both gametophytes and coupling embryo development with chlorophyll synthesis.
原质体是多命运质体生物发生的重要前体，包括叶绿体分化，叶绿体是植物光合作用的动力源。拟南芥锚蛋白重复蛋白（AKRP，AT5G66055）是一种定位于质体的蛋白，在质体分化和形态发生中具有推定功能。其功能丧失会导致胚胎发育停滞。AKRP在受精前是否至关重要仍未得到解决。在这里，我们利用反向遗传学报道了一个新的等位基因，与先前报道的等位基因相比，该等位基因突变胚胎的频率降低（<13%）。该等位基因影响雄配子体和雌配子体，导致活力降低、花粉管吸引能力丧失、配子细胞命运改变以及胚胎停滞，胚胎缺乏叶绿素。AKRP广泛表达，AKRP-GFP融合蛋白定位于两种配子体的质体、分离的叶绿体中，并在花粉和花粉管中与质体标记物共定位。该等位基因的细胞类型特异性互补暗示了AKRP可能发挥重要作用的发育时间。我们的研究结果为AKRP在配子体分化以及将胚胎发育与叶绿素合成耦合中的关键作用提供了合理的见解。
