Transgenic creeping bentgrass overexpressing Osa‐miR393aexhibits altered plant development and improved multiple stress tolerance
Friday, 2018/07/13 | 08:08:31
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Junming Zhao, Shuangrong Yuan, Man Zhou, Ning Yuan, Zhigang Li, Qian Hu, Frank G. Bethea Jr., Haibo Liu, Shigui Li, Hong Luo Plant Biotechnology Journal - First published: 06 June 2018 - https://doi.org/10.1111/pbi.12960 SummaryMicroRNA393 (miR393) has been implicated in plant growth, development and multiple stress responses in annual species such as Arabidopsis and rice. However, the role of miR393 in perennial grasses remains unexplored. Creeping bentgrass (Agrostis stoloniferaL.) is an environmentally and economically important C3 cool‐season perennial turfgrass. Understanding how miR393 functions in this representative turf species would allow the development of novel strategies in genetically engineering grass species for improved abiotic stress tolerance. We have generated and characterized transgenic creeping bentgrass plants overexpressing rice pri‐miR393a (Osa‐miR393a). We found that Osa‐miR393a transgenics had fewer, but longer tillers, enhanced drought stress tolerance associated with reduced stomata density and denser cuticles, improved salt stress tolerance associated with increased uptake of potassium and enhanced heat stress tolerance associated with induced expression of small heat‐shock protein in comparison with wild‐type controls. We also identified two targets of miR393, AsAFB2 and AsTIR1, whose expression is repressed in transgenics. Taken together, our results revealed the distinctive roles of miR393/target module in plant development and stress responses between creeping bentgrass and other annual species, suggesting that miR393 would be a promising candidate for generating superior crop cultivars with enhanced multiple stress tolerance, thus contributing to agricultural productivity.
See https://onlinelibrary.wiley.com/doi/abs/10.1111/pbi.12960
Figure 1: Development of wild‐type (WT) and transgenic (TG) plants. (a) Ten‐week‐old wild‐type and transgenic plants initiated from a single tiller. Bar = 10 cm. (b) Tiller number of 10‐week‐old wild‐type and transgenic plants initiated from a single tiller. (c) Close‐up of the longest tillers from wild‐type and transgenic plants. Bar = 5 cm. (d) All internodes from the representative longest tiller were sliced from top to bottom and displayed in order from left to right. Bar = 5 cm. (e) Root system of 10‐week‐old wild‐type and transgenic plants initiated from a single tiller. Bar = 5 cm. (f) Top fully developed leaf from the representative tillers of wild‐type and transgenic plants. Bar = 5 cm. (g) Cross‐sectional images of wild‐type and transgenic leaves. Bar = 200 μm. (h) Cross‐sectional images of wild‐type and transgenic stems. Bar = 200 μm. (i) Tiller number in wild‐type and transgenic plants 5 and 10 weeks after initiation from a single tiller. (j) Shoot number in wild‐type and transgenic plants 30, 60 and 90 days after initiation from a single tiller. (k) Statistical analysis of the longest tiller length between representative wild‐type and transgenic plants. (l) Statistical analysis of biomass between representative wild‐type and transgenic plants. (m) Statistical analysis of the leaf blade width between representative wild‐type and transgenic plants. (n) Statistical analysis of the stem diameter between representative wild‐type and transgenic plants. (o) Fully developed WT and TG lines (TG1, TG4) with ten tillers grown in cone‐tainers were mowed weekly to the same height. Clipping fresh weight was measured at the end of 1st, 2nd and 3rd weeks. Data are presented as means (n = at least 5), and error bars represent SD. Asterisks indicate a significant difference between the wild‐type and each transgenic line at *P < 0.05; **P < 0.01; and ***P < 0.001 by Student's t‐test. |
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