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AbhemC encoding porphobilinogen deaminase plays an important role in chlorophyll biosynthesis and function in albino Ananas comosus var. bracteatus leaves

BACKGROUND: The chimeric leaves of Ananas comosus var. bracteatus are composed of normal green parts (Grs) and albino white parts (Whs). Although the underlying mechanism of albinism in A. comosus var. bracteatus leaves is not fully understood, it is likely associated with the chlorophyll (Chl) bios...

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Autores principales: Xue, Yanbin, Li, Xia, Mao, Meiqin, He, Yehua, Owusu Adjei, Mark, Zhou, Xuzixin, Hu, Hao, Liu, Jiawen, Li, Xi, Ma, Jun
Formato: Online Artículo Texto
Lenguaje:English
Publicado: PeerJ Inc. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8018242/
https://www.ncbi.nlm.nih.gov/pubmed/33850657
http://dx.doi.org/10.7717/peerj.11118
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author Xue, Yanbin
Li, Xia
Mao, Meiqin
He, Yehua
Owusu Adjei, Mark
Zhou, Xuzixin
Hu, Hao
Liu, Jiawen
Li, Xi
Ma, Jun
author_facet Xue, Yanbin
Li, Xia
Mao, Meiqin
He, Yehua
Owusu Adjei, Mark
Zhou, Xuzixin
Hu, Hao
Liu, Jiawen
Li, Xi
Ma, Jun
author_sort Xue, Yanbin
collection PubMed
description BACKGROUND: The chimeric leaves of Ananas comosus var. bracteatus are composed of normal green parts (Grs) and albino white parts (Whs). Although the underlying mechanism of albinism in A. comosus var. bracteatus leaves is not fully understood, it is likely associated with the chlorophyll (Chl) biosynthesis. In this biosynthetic process, porphobilinogen deaminase (PBGD) plays a crucial role by catalyzing the conversion of porphobilinogen (PBG) to uroporphyrinogen III (Urogen III). Therefore, its encoding gene AbhemC was investigated here in association with Chl biosynthesis and albinism in chimeric A. comosus var. bracteatus leaves. METHODS: The Chl content, main Chl biosynthesis precursor content, and main enzyme activity were determined and compared between the Whs and Grs of A. comosus var. bracteatus leaves. In addition, AbhemC was cloned and its transcriptional expression and prokaryotic protein expression were analyzed. Furthermore, RNAi-mediated silencing of AbhemC was produced and assessed in tobacco plants. RESULTS: The concentration of Chl a and Chl b in the Grs was significantly higher than that in the Whs, respectively. Additionally, the content of the Chl biosynthesis precursor Urogen III decreased significantly in the Whs compared with the Grs. Thus, the transition of PBG to Urogen III may be the first rate-limiting step leading to albinism in the chimeric leaves of A. comosus var. bracteatus. The gene AbhemC comprised 1,135 bp and was encoded into a protein with 371 amino acids; phylogenetically, AbhemC was most closely related to hemC of pineapple. Prokaryotic expression and in vitro enzyme activity analysis showed that the cloned mRNA sequence of AbhemC was successfully integrated and had PBGD activity. Compared with control plants, transgenic tobacco leaves with pFGC5941-AbhemC-RNAi vector were substantially less green with significantly reduced hemC expression and Chl content, as well as reduced PBGD enzyme activity and significantly decreased content of Chl biosynthesis precursors from Urogen III onwards. Our results suggest that the absence of hemC expression reduces the enzyme activity of PBGD, which blocks the transition of PBG to Urogen III, and in turn suppresses Chl synthesis leading to the pale-green leaf color. Therefore, we suggest that AbhemC plays an important role in Chl synthesis and may be an important factor in the albinism of A. comosus var. bracteatus leaves.
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spelling pubmed-80182422021-04-12 AbhemC encoding porphobilinogen deaminase plays an important role in chlorophyll biosynthesis and function in albino Ananas comosus var. bracteatus leaves Xue, Yanbin Li, Xia Mao, Meiqin He, Yehua Owusu Adjei, Mark Zhou, Xuzixin Hu, Hao Liu, Jiawen Li, Xi Ma, Jun PeerJ Biochemistry BACKGROUND: The chimeric leaves of Ananas comosus var. bracteatus are composed of normal green parts (Grs) and albino white parts (Whs). Although the underlying mechanism of albinism in A. comosus var. bracteatus leaves is not fully understood, it is likely associated with the chlorophyll (Chl) biosynthesis. In this biosynthetic process, porphobilinogen deaminase (PBGD) plays a crucial role by catalyzing the conversion of porphobilinogen (PBG) to uroporphyrinogen III (Urogen III). Therefore, its encoding gene AbhemC was investigated here in association with Chl biosynthesis and albinism in chimeric A. comosus var. bracteatus leaves. METHODS: The Chl content, main Chl biosynthesis precursor content, and main enzyme activity were determined and compared between the Whs and Grs of A. comosus var. bracteatus leaves. In addition, AbhemC was cloned and its transcriptional expression and prokaryotic protein expression were analyzed. Furthermore, RNAi-mediated silencing of AbhemC was produced and assessed in tobacco plants. RESULTS: The concentration of Chl a and Chl b in the Grs was significantly higher than that in the Whs, respectively. Additionally, the content of the Chl biosynthesis precursor Urogen III decreased significantly in the Whs compared with the Grs. Thus, the transition of PBG to Urogen III may be the first rate-limiting step leading to albinism in the chimeric leaves of A. comosus var. bracteatus. The gene AbhemC comprised 1,135 bp and was encoded into a protein with 371 amino acids; phylogenetically, AbhemC was most closely related to hemC of pineapple. Prokaryotic expression and in vitro enzyme activity analysis showed that the cloned mRNA sequence of AbhemC was successfully integrated and had PBGD activity. Compared with control plants, transgenic tobacco leaves with pFGC5941-AbhemC-RNAi vector were substantially less green with significantly reduced hemC expression and Chl content, as well as reduced PBGD enzyme activity and significantly decreased content of Chl biosynthesis precursors from Urogen III onwards. Our results suggest that the absence of hemC expression reduces the enzyme activity of PBGD, which blocks the transition of PBG to Urogen III, and in turn suppresses Chl synthesis leading to the pale-green leaf color. Therefore, we suggest that AbhemC plays an important role in Chl synthesis and may be an important factor in the albinism of A. comosus var. bracteatus leaves. PeerJ Inc. 2021-03-30 /pmc/articles/PMC8018242/ /pubmed/33850657 http://dx.doi.org/10.7717/peerj.11118 Text en ©2021 Xue et al. https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited.
spellingShingle Biochemistry
Xue, Yanbin
Li, Xia
Mao, Meiqin
He, Yehua
Owusu Adjei, Mark
Zhou, Xuzixin
Hu, Hao
Liu, Jiawen
Li, Xi
Ma, Jun
AbhemC encoding porphobilinogen deaminase plays an important role in chlorophyll biosynthesis and function in albino Ananas comosus var. bracteatus leaves
title AbhemC encoding porphobilinogen deaminase plays an important role in chlorophyll biosynthesis and function in albino Ananas comosus var. bracteatus leaves
title_full AbhemC encoding porphobilinogen deaminase plays an important role in chlorophyll biosynthesis and function in albino Ananas comosus var. bracteatus leaves
title_fullStr AbhemC encoding porphobilinogen deaminase plays an important role in chlorophyll biosynthesis and function in albino Ananas comosus var. bracteatus leaves
title_full_unstemmed AbhemC encoding porphobilinogen deaminase plays an important role in chlorophyll biosynthesis and function in albino Ananas comosus var. bracteatus leaves
title_short AbhemC encoding porphobilinogen deaminase plays an important role in chlorophyll biosynthesis and function in albino Ananas comosus var. bracteatus leaves
title_sort abhemc encoding porphobilinogen deaminase plays an important role in chlorophyll biosynthesis and function in albino ananas comosus var. bracteatus leaves
topic Biochemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8018242/
https://www.ncbi.nlm.nih.gov/pubmed/33850657
http://dx.doi.org/10.7717/peerj.11118
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