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Asymmetric transcriptomic signatures between the cob and florets in the maize ear under optimal- and low-nitrogen conditions at silking, and functional characterization of amino acid transporters ZmAAP4 and ZmVAAT3.

Pan X, Hasan MM, Li Y, Liao C, Zheng H, Liu R, Li X - J. Exp. Bot. (2015)

Bottom Line: Fourteen genes responsive specifically to LN provided potential molecular markers for N-efficient maize breeding.We further functionally characterized two newly identified broad-spectrum amino acid transporters, ZmAAP4 and ZmVAAT3, that showed distinct expression patterns in the cob and florets and potentially important roles in amino-N mobilization in the ear.While both proteins could transport various amino acids into yeast or Arabidopsis cells, ZmAAP4 appeared to have higher efficiencies than ZmVAAT3 in transporting seven out of 22 examined amino acids.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Nutrition, China Agricultural University, Beijing 100193, China.

No MeSH data available.


(A) Gene expression levels of ZmAAP4 and ZmVAAT3 in different maize tissues. The gene expression level in the root was normalized to 1 when compared with the other four tissues or organs, and that of the cob was normalized to 1 when compared with that of florets within the ear. (B) Subcellular localization of ZmAAP4 and ZmVAAT3 by transient expression of GFP fusion proteins in onion epidermal cells.
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Figure 8: (A) Gene expression levels of ZmAAP4 and ZmVAAT3 in different maize tissues. The gene expression level in the root was normalized to 1 when compared with the other four tissues or organs, and that of the cob was normalized to 1 when compared with that of florets within the ear. (B) Subcellular localization of ZmAAP4 and ZmVAAT3 by transient expression of GFP fusion proteins in onion epidermal cells.

Mentions: Consistent with dynamic assimilated-N translocation and amino acid interconversion in the ear, numerous C/N transport and metabolism genes, including 21 putative amino acid transporters, were found with differential expression in the cob and florets (Supplementary Table S5). To bridge gene expression with physiological functions of amino acid transporters in the ear and comparatively analyse their transport capabilities, we cloned GRMZM2G110195_T01 and GRMZM2G080843_T01 for functional characterization. GRMZM2G110195_T01 (ZmAAP4) encodes the putative amino acid permease 4, with 12 transmembrane domains (Supplementary Dataset S1), and had balanced expression in the cob and florets according to the DGE data. GRMZM2G080843_T01 (ZmVAAT3) encodes the putative vacuolar amino acid transporter 3, with 11 transmembrane domains (Supplementary Dataset S1), and was preferentially expressed in florets. At the silking stage, RT-qPCR showed that ZmAAP4 had higher expression levels in the ear (a similar level in the cob and florets) and stem than in the root, leaf and tassel (Fig. 8A). ZmVAAT3 was expressed in the root, tassel and ear, but not in the leaf and stem (Fig. 8A). It showed ~70-fold higher expression in the ear compared to that in the root. In the ear, its expression level in the florets is nearly 170-fold higher than in the cob (Fig. 8A). Next, we used GFP tagged constructs to examine where ZmAAP4 and ZmVAAT3 are expressed in the cell. We found that when expressed in the onion epidermal cells, ZmAAP4 was mainly located on the plasma membrane and in the nucleus, whereas ZmVAAT3 was mainly located on the plasma and nuclear membranes (Fig. 8B).


Asymmetric transcriptomic signatures between the cob and florets in the maize ear under optimal- and low-nitrogen conditions at silking, and functional characterization of amino acid transporters ZmAAP4 and ZmVAAT3.

Pan X, Hasan MM, Li Y, Liao C, Zheng H, Liu R, Li X - J. Exp. Bot. (2015)

(A) Gene expression levels of ZmAAP4 and ZmVAAT3 in different maize tissues. The gene expression level in the root was normalized to 1 when compared with the other four tissues or organs, and that of the cob was normalized to 1 when compared with that of florets within the ear. (B) Subcellular localization of ZmAAP4 and ZmVAAT3 by transient expression of GFP fusion proteins in onion epidermal cells.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
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getmorefigures.php?uid=PMC4588875&req=5

Figure 8: (A) Gene expression levels of ZmAAP4 and ZmVAAT3 in different maize tissues. The gene expression level in the root was normalized to 1 when compared with the other four tissues or organs, and that of the cob was normalized to 1 when compared with that of florets within the ear. (B) Subcellular localization of ZmAAP4 and ZmVAAT3 by transient expression of GFP fusion proteins in onion epidermal cells.
Mentions: Consistent with dynamic assimilated-N translocation and amino acid interconversion in the ear, numerous C/N transport and metabolism genes, including 21 putative amino acid transporters, were found with differential expression in the cob and florets (Supplementary Table S5). To bridge gene expression with physiological functions of amino acid transporters in the ear and comparatively analyse their transport capabilities, we cloned GRMZM2G110195_T01 and GRMZM2G080843_T01 for functional characterization. GRMZM2G110195_T01 (ZmAAP4) encodes the putative amino acid permease 4, with 12 transmembrane domains (Supplementary Dataset S1), and had balanced expression in the cob and florets according to the DGE data. GRMZM2G080843_T01 (ZmVAAT3) encodes the putative vacuolar amino acid transporter 3, with 11 transmembrane domains (Supplementary Dataset S1), and was preferentially expressed in florets. At the silking stage, RT-qPCR showed that ZmAAP4 had higher expression levels in the ear (a similar level in the cob and florets) and stem than in the root, leaf and tassel (Fig. 8A). ZmVAAT3 was expressed in the root, tassel and ear, but not in the leaf and stem (Fig. 8A). It showed ~70-fold higher expression in the ear compared to that in the root. In the ear, its expression level in the florets is nearly 170-fold higher than in the cob (Fig. 8A). Next, we used GFP tagged constructs to examine where ZmAAP4 and ZmVAAT3 are expressed in the cell. We found that when expressed in the onion epidermal cells, ZmAAP4 was mainly located on the plasma membrane and in the nucleus, whereas ZmVAAT3 was mainly located on the plasma and nuclear membranes (Fig. 8B).

Bottom Line: Fourteen genes responsive specifically to LN provided potential molecular markers for N-efficient maize breeding.We further functionally characterized two newly identified broad-spectrum amino acid transporters, ZmAAP4 and ZmVAAT3, that showed distinct expression patterns in the cob and florets and potentially important roles in amino-N mobilization in the ear.While both proteins could transport various amino acids into yeast or Arabidopsis cells, ZmAAP4 appeared to have higher efficiencies than ZmVAAT3 in transporting seven out of 22 examined amino acids.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Nutrition, China Agricultural University, Beijing 100193, China.

No MeSH data available.