AUTHOR=Liang Shan , Hu Ming-li , Lin Hao-chuan , He Han-jun , Ning Xi-ping , Peng Pei-pei , Lu Guo-hui , Sun Shu-lan , Wang Xiao-jing , Wang Ying-qiang , Wu Hong 

TITLE=Transcriptional regulations of pollen tube reception are associated with the fertility of the ginger species Zingiber zerumbet and Zingiber corallinum

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1099250

DOI=10.3389/fpls.2023.1099250

ISSN=1664-462X

ABSTRACT=<p><italic>Zingiber zerumbet</italic> and <italic>Zingiber corallinum</italic> are economically valuable species in the genus <italic>Zingiber</italic>. While <italic>Z. corallinum</italic> is sexually active, <italic>Z. zerumbet</italic> adopts clonal propagation, although it has the potential for sexual reproduction. It is unclear so far at which step during the sexual reproduction of <italic>Z. zerumbet</italic> inhibition occurs, and what are the regulatory mechanisms underlying this inhibition. Here, by comparing with the fertile species <italic>Z. corallinum</italic> using microscopy-based methods, we show that rare differences were observed in <italic>Z. zerumbet</italic> up to the point when the pollen tubes invaded the ovules. However, a significantly higher percentage of ovules still contained intact pollen tubes 24 h after pollination, suggesting pollen tube rupture was impaired in this species. Further RNA-seq analysis generated accordant results, showing that the transcription of <italic>ANX</italic> and <italic>FER</italic>, as well as genes for the partners in the same complexes (e.g., BUPS and LRE, respectively), and those putative peptide signals (e.g., RALF34), were timely activated in <italic>Z. corallinum</italic>, which ensured the pollen tubes being able to grow, reorient to ovules, and receipt by embryo sacs. In <italic>Z. zerumbet</italic>, genes for these complexes were cooperatively suppressed, which would result in the maintenance of PT integrity due to the disruption of RALF34-ANX/BUPS signaling in PT and the failure of PT reception by an active synergid due to the insufficiency of the synergid-harbored FER/LRE complex. Taking the results from the cytological and RNA-seq studies together, a model is proposed to illustrate the possible regulation mechanisms in <italic>Z. zerumbet</italic> and <italic>Z. corallinum</italic>, in which the regulations for pollen tube rupture and reception are proposed as the barrier for sexual reproduction in <italic>Z. zerumbet</italic>.</p>