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BraLTP1, a lipid transfer protein gene involved in epicuticular wax deposition, cell proliferation and flower development in Brassica napus.

Liu F, Xiong X, Wu L, Fu D, Hayward A, Zeng X, Cao Y, Wu Y, Li Y, Wu G - PLoS ONE (2014)

Bottom Line: Overexpression of BnaLTP1 in B. napus caused abnormal green coloration and reduced wax deposition on leaves and detailed wax analysis revealed 17-80% reduction in various major wax components, which resulted in significant water-loss relative to wild type.This was consistent with altered expression of a a number of ABC model genes related to flower development.Together, these results suggest that BraLTP1 is a new nsLTP gene involved in wax production or deposition, with additional direct or indirect effects on cell division and flower development.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Oil Crop Biology of the Ministry of Agriculture, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, China.

ABSTRACT
Plant non-specific lipid transfer proteins (nsLTPs) constitute large multigene families that possess complex physiological functions, many of which remain unclear. This study isolated and characterized the function of a lipid transfer protein gene, BraLTP1 from Brassica rapa, in the important oilseed crops Brassica napus. BraLTP1 encodes a predicted secretory protein, in the little known VI Class of nsLTP families. Overexpression of BnaLTP1 in B. napus caused abnormal green coloration and reduced wax deposition on leaves and detailed wax analysis revealed 17-80% reduction in various major wax components, which resulted in significant water-loss relative to wild type. BnaLTP1 overexpressing leaves exhibited morphological disfiguration and abaxially curled leaf edges, and leaf cross-sections revealed cell overproliferation that was correlated to increased cytokinin levels (tZ, tZR, iP, and iPR) in leaves and high expression of the cytokinin biosynthsis gene IPT3. BnaLTP1-overexpressing plants also displayed morphological disfiguration of flowers, with early-onset and elongated carpel development and outwardly curled stamen. This was consistent with altered expression of a a number of ABC model genes related to flower development. Together, these results suggest that BraLTP1 is a new nsLTP gene involved in wax production or deposition, with additional direct or indirect effects on cell division and flower development.

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Overexpression of BraLTP1 promotes cell proliferation.(A) The weight of per unit leaf area of wild type (WT), BraLTP1-20 and BraLTP1-22 and their segregated negative controls BraLTP1-20N and BraLTP1-22N. Leaf disks were collected from the fourth fully-expanded leaf from the apex taken from 8-week-old plants. Data are the mean±SD from three independent experiments using leaves of five plants. **Significant differences at the levels of P<0.01. (B) Representative leaf cross-sections of segregating 35S::BraLTP1 and WT plants. The fourth fully-expanded leaf from the apex were taken from 6-week old plants of WT, 35S::BraLTP1 transgenic plants (BraLTP1-20 and BraLTP1-22), and  segregates of these two lines (BraLTP1-20N and BraLTP1-22N). The experiments were repeated for 3 times. Bar = 200 µm.
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pone-0110272-g007: Overexpression of BraLTP1 promotes cell proliferation.(A) The weight of per unit leaf area of wild type (WT), BraLTP1-20 and BraLTP1-22 and their segregated negative controls BraLTP1-20N and BraLTP1-22N. Leaf disks were collected from the fourth fully-expanded leaf from the apex taken from 8-week-old plants. Data are the mean±SD from three independent experiments using leaves of five plants. **Significant differences at the levels of P<0.01. (B) Representative leaf cross-sections of segregating 35S::BraLTP1 and WT plants. The fourth fully-expanded leaf from the apex were taken from 6-week old plants of WT, 35S::BraLTP1 transgenic plants (BraLTP1-20 and BraLTP1-22), and segregates of these two lines (BraLTP1-20N and BraLTP1-22N). The experiments were repeated for 3 times. Bar = 200 µm.

Mentions: In addition to the wax phenotype, the cellular morphology and weight of per unit leaf area was examined (Fig. 7A and B). BraLTP1-20 and BraLTP1-22 leaves were 0.033 g cm−2 and 0.031 g cm−2 respectively, significantly higher than negative segregants and wild type, which varied from 0.024 g cm−2 to 0.026 g cm−2 (P<0.01) (Fig. 7A). To examine changes at the cellular, structural level, paraffin-wax-embedded leaf cross-sections stained with Safranin and fast green were examined. This demonstrated that in BraLTP1 overexpressing lines, the cellular layer of both palisade tissue and parenchyma tissue was increased; with palisade cells, parenchyma cells and epidermic cells smaller and more compact than negative segregants and wild type sections (Fig. 7B). Thus, increased cellular layering and a compact cell arrangement likely led to the increase in weight for per unit leaf area. This underlying change in leaf cell layer number and density likely contributes to the visible morphological defects including leaf curling.


BraLTP1, a lipid transfer protein gene involved in epicuticular wax deposition, cell proliferation and flower development in Brassica napus.

Liu F, Xiong X, Wu L, Fu D, Hayward A, Zeng X, Cao Y, Wu Y, Li Y, Wu G - PLoS ONE (2014)

Overexpression of BraLTP1 promotes cell proliferation.(A) The weight of per unit leaf area of wild type (WT), BraLTP1-20 and BraLTP1-22 and their segregated negative controls BraLTP1-20N and BraLTP1-22N. Leaf disks were collected from the fourth fully-expanded leaf from the apex taken from 8-week-old plants. Data are the mean±SD from three independent experiments using leaves of five plants. **Significant differences at the levels of P<0.01. (B) Representative leaf cross-sections of segregating 35S::BraLTP1 and WT plants. The fourth fully-expanded leaf from the apex were taken from 6-week old plants of WT, 35S::BraLTP1 transgenic plants (BraLTP1-20 and BraLTP1-22), and  segregates of these two lines (BraLTP1-20N and BraLTP1-22N). The experiments were repeated for 3 times. Bar = 200 µm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4196963&req=5

pone-0110272-g007: Overexpression of BraLTP1 promotes cell proliferation.(A) The weight of per unit leaf area of wild type (WT), BraLTP1-20 and BraLTP1-22 and their segregated negative controls BraLTP1-20N and BraLTP1-22N. Leaf disks were collected from the fourth fully-expanded leaf from the apex taken from 8-week-old plants. Data are the mean±SD from three independent experiments using leaves of five plants. **Significant differences at the levels of P<0.01. (B) Representative leaf cross-sections of segregating 35S::BraLTP1 and WT plants. The fourth fully-expanded leaf from the apex were taken from 6-week old plants of WT, 35S::BraLTP1 transgenic plants (BraLTP1-20 and BraLTP1-22), and segregates of these two lines (BraLTP1-20N and BraLTP1-22N). The experiments were repeated for 3 times. Bar = 200 µm.
Mentions: In addition to the wax phenotype, the cellular morphology and weight of per unit leaf area was examined (Fig. 7A and B). BraLTP1-20 and BraLTP1-22 leaves were 0.033 g cm−2 and 0.031 g cm−2 respectively, significantly higher than negative segregants and wild type, which varied from 0.024 g cm−2 to 0.026 g cm−2 (P<0.01) (Fig. 7A). To examine changes at the cellular, structural level, paraffin-wax-embedded leaf cross-sections stained with Safranin and fast green were examined. This demonstrated that in BraLTP1 overexpressing lines, the cellular layer of both palisade tissue and parenchyma tissue was increased; with palisade cells, parenchyma cells and epidermic cells smaller and more compact than negative segregants and wild type sections (Fig. 7B). Thus, increased cellular layering and a compact cell arrangement likely led to the increase in weight for per unit leaf area. This underlying change in leaf cell layer number and density likely contributes to the visible morphological defects including leaf curling.

Bottom Line: Overexpression of BnaLTP1 in B. napus caused abnormal green coloration and reduced wax deposition on leaves and detailed wax analysis revealed 17-80% reduction in various major wax components, which resulted in significant water-loss relative to wild type.This was consistent with altered expression of a a number of ABC model genes related to flower development.Together, these results suggest that BraLTP1 is a new nsLTP gene involved in wax production or deposition, with additional direct or indirect effects on cell division and flower development.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Oil Crop Biology of the Ministry of Agriculture, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, China.

ABSTRACT
Plant non-specific lipid transfer proteins (nsLTPs) constitute large multigene families that possess complex physiological functions, many of which remain unclear. This study isolated and characterized the function of a lipid transfer protein gene, BraLTP1 from Brassica rapa, in the important oilseed crops Brassica napus. BraLTP1 encodes a predicted secretory protein, in the little known VI Class of nsLTP families. Overexpression of BnaLTP1 in B. napus caused abnormal green coloration and reduced wax deposition on leaves and detailed wax analysis revealed 17-80% reduction in various major wax components, which resulted in significant water-loss relative to wild type. BnaLTP1 overexpressing leaves exhibited morphological disfiguration and abaxially curled leaf edges, and leaf cross-sections revealed cell overproliferation that was correlated to increased cytokinin levels (tZ, tZR, iP, and iPR) in leaves and high expression of the cytokinin biosynthsis gene IPT3. BnaLTP1-overexpressing plants also displayed morphological disfiguration of flowers, with early-onset and elongated carpel development and outwardly curled stamen. This was consistent with altered expression of a a number of ABC model genes related to flower development. Together, these results suggest that BraLTP1 is a new nsLTP gene involved in wax production or deposition, with additional direct or indirect effects on cell division and flower development.

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