Localization of BEN1-LIKE protein and nuclear degradation during development of metaphloem sieve elements in Triticum aestivum L.
Metaphloem sieve elements (MSEs) in the developing caryopsis of Triticum aestivum L. undergo a unique type of programmed cell death (PCD); cell organelles gradually degrade with the MSE differentiation while mature sieve elements keep active. This study focuses on locating BEN1-LIKE protein and nuclear degradation in differentiating MSEs of wheat. Transmission electron microscopy (TEM) showed that nuclei degraded in MSE development. First, the degradation started at 2-3 days after flowering (DAF). The degraded fragments were then swallowed by phagocytic vacuoles at 4 DAF. Finally, nuclei almost completely degraded at 5 DAF. We measured the BEN1-LIKE protein expression in differentiating MSEs. In situ hybridization showed that BEN1-LIKE mRNA was a more obvious hybridization signal at 3-4 DAF at the microscopic level. Immuno-electron microscopy further revealed that BEN1-LIKE protein was mainly localized in MSE nuclei. Furthermore, MSE differentiation was tested using a TSQ Zn2+ fluorescence probe which showed that the dynamic change of Zn2+ accumulation was similar to BEN1-LIKE protein expression. These results suggest that nucleus degradation in wheat MSEs is associated with BEN1-LIKE protein and that the expression of this protein may be regulated by Zn2+ accumulation variation.
Huazhong Agricultural University Laboratory of Cell Biology, College of Life Science and Technology Wuhan, Hubei 430070 China.
Jingtong
J
Cai
Huazhong Agricultural University Laboratory of Cell Biology, College of Life Science and Technology Wuhan, Hubei 430070 China.
Zhihui
Z
Zhang
Huazhong Agricultural University Laboratory of Cell Biology, College of Life Science and Technology Wuhan, Hubei 430070 China.
Zhuqing
Z
Zhou
Huazhong Agricultural University Laboratory of Cell Biology, College of Life Science and Technology Wuhan, Hubei 430070 China.
Wenli
W
Yang
Huazhong Agricultural University Laboratory of Cell Biology, College of Life Science and Technology Wuhan, Hubei 430070 China.
Yang
Y
Liu
Huazhong Agricultural University College of Plant Sciences & Technology Wuhan, Hubei 430070 China.
Fangzhu
F
Mei
Huazhong Agricultural University College of Plant Sciences & Technology Wuhan, Hubei 430070 China.
Guangsheng
G
Zhou
Huazhong Agricultural University Laboratory of Cell Biology, College of Life Science and Technology Wuhan, Hubei 430070 China.
Likai
L
Wang
D002467:Cell Nucleus / Q000378:metabolism*; D005453:Fluorescence; D017403:In Situ Hybridization; D016253:Microscopy, Immunoelectron; D052585:Phloem / Q000254:growth & development*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D059748:Proteolysis; D012333:RNA, Messenger / Q000235:genetics; D014908:Triticum / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism
D010940:Plant Proteins; D012333:RNA, Messenger; D015032:Zinc
BEN1-LIKE protein; MSEs; Triticum aestivum L.; immuno-electron microcoy; in-situ hybridization