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Ethylene signaling is critical for synergid cell functional specification and pollen tube attraction
Author(s) -
Zhang Cheng,
Teng XiaoDong,
Zheng QuanQuan,
Zhao YanYun,
Lu JieYang,
Wang Yichuan,
Guo Hongwei,
Yang ZhongNan
Publication year - 2018
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.14027
Subject(s) - pollen tube , attraction , pollen , tube (container) , biology , microbiology and biotechnology , botany , engineering , pollination , mechanical engineering , linguistics , philosophy
Summary ETHYLENE INSENSITIVE 3 ( EIN 3) is a key regulator of ethylene signaling, and EIN 3‐ BINDING F‐ BOX 1 ( EBF 1) and EBF 2 are responsible for EIN 3 degradation. Previous reports have shown that the ebf1 ebf2 double homozygous mutant cannot be identified. In this study, the genetic analysis revealed that the ebf1 ebf2 female gametophyte is defective. The pollination experiment showed that ebf1 ebf2 ovules failed to attract pollen tubes. In female gametophyte/ovule, the synergid cell is responsible for pollen tube attraction. Observation of the pEIN 3:: EIN 3‐ GFP transgenic lines showed that EIN 3 signal was over‐accumulated at the micropylar end of ebf1 ebf2 female gametophyte. The overexpression of stabilized EIN 3 in synergid cell led to the defect of pollen tube guidance. These results suggested that the over‐accumulated EIN 3 in ebf1 ebf2 synergid cell blocks its pollen tube attraction which leads to the failure of ebf1 ebf2 homozygous plant. We identified that EIN 3 directly activated the expression of a sugar transporter , SENESCENCE‐ASSOCIATED GENE29 ( SAG 29/ SWEET 15 ). Overexpression of SAG 29 in synergid cells blocked pollen tube attraction, suggesting that SAG 29 might play a role in ethylene signaling to repel pollen tube entry. Taken together, our study reveals that strict control of ethylene signaling is critical for the synergid cell function during plant reproduction.