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Gibberellins (GAs) play a key role in the transition from vegetative growth to flowering and the GA receptor GID1 (GIBBERELLIN INSENSITIVE DWARF1) is the central part of GA-signaling. The differential expression of SvGID1 was found in the transcriptome sequencing in our previous study, which was further verified at different stages of flowering of Salix viminalis. In order to reveal the function GID1 of S. viminalis, two genes of SvGID1b and SvGID1c were cloned and transformed into Arabidopsis thaliana, respectively. The results showed that the full ORF length of SvGID1b and SvGID1c genes were both 1035 bp, encoding 344 amino acids, which were typical globular proteins. The peptide chain contained more α-helix structure, and had 99% similarity with GID1b and GID1c amino acid sequences of Salix suchowensis. Phylogenetic analysis showed that SvGID1s had close genetic relationship with woody plants such as Populus alba and Populus tomentosa, and had far genetic relationship with rice. After overexpression in A. thaliana, the total gibberellin, active gibberellin content and the expression level of GA3ox1, the key gene for GA4 synthesis, were not significantly different from those in the wild-type, while the expression levels of FUL, SOC1 and FT, the key genes for flowering in plants, were increased, and the expression levels of FLC and GAI were decreased. The ectopic expression of SvGID1s increased the sensitivity of plants to gibberellin and enhanced gibberellin effect, caused early bolting, budding and flowering, led to higher plant, longer hypocotyl and other phenomena. The results provide a theoretical basis for clarifying the regulation of gibberellin on flower bud differentiation of flowering plants.

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Homeodomain-leucine zipper (HD-Zip) genes encode plant-specific transcription factors, which play important roles in plant growth, development, and response to environmental stress. These genes have not been fully studied in allopolyploid Brassica napus, an important kind of oil crop. In this study, 165 HD-Zip genes were identified in B. napus and classified into four subfamilies. If proteins belong to the same subfamily, they exhibit similarities in gene structure, motifs, and domain distribution patterns. BnHD-Zip genes were unevenly distributed in the An and Cn subgenomes. Whole genome triplication (WGT) events may be major mechanisms accounting for this gene family expansion. Orthologous gene analysis showed that the process of this gene family expansion was accompanied by domain loss. We further found three genes homologous to HB7 and three genes homologous to HB12, all induced by PEG, ABA, and NaCl treatment. HB7 could not form homodimers but could form heterodimers with HB12 based on yeast two-hybrid assays. The results of this study provide valuable information for further exploration of the HD-Zip gene family in B. napus.

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Understanding the impacts and constraints of climate change on the geographical distribution of wild Akebia trifoliata is crucial for its sustainable management and economic development as a medicinal material or fruit. In this study, according to the first-hand information obtained from field investigation, the distribution and response to climate change of A. trifoliata were studied by the MaxEnt model and ArcGIS. The genetic diversity and population structure of 21 natural populations of A. trifoliata were studied by simple sequence repeat (SSR) markers. The results showed that the most important bioclimatic variable limiting the distribution of A. trifoliata was the Mean Temperature of Coldest Quarter (bio11). Under the scenarios SSP1-2.6 and SSP2-4.5, the suitable area of A. trifoliata in the world will remain stable, and the suitable area will increase significantly under the scenarios of SSP3-7.0 and SSP5-8.5. Under the current climate scenario, the suitable growth regions of A. trifoliata in China were 79.9-122.7°E and 21.5-37.5°N. Under the four emission scenarios in the future, the geometric center of the suitable distribution regions of Akebia trifoliata in China will move to the north. The clustering results of 21 populations of A. trifoliata analyzed by SSR markers showed that they had a trend of evolution from south to north.

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NOVELTY STATEMENT: Salix viminalis, a dioecious shrub willow, has been widely used in phytoremediation, yet sexually differences in tolerance to cadmium of which remained unclear. This study focused on different responses to cadmium stress between roots of male and female S. viminalis. Results show that male plants of S. viminalis have stronger cadmium tolerance than female plants, which indicates male S. viminalis should be more considered to be applied for phytoremediation and ecological restoration of cadmium-accumulated soil considering cadmium tolerance characteristics. The findings can provide valuable evidence and insights for researches focused on phytoremediation with dioecious woody plants and sexual dimorphism under abiotic stress.

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Dirigent proteins (DIRs) are critically involved in the formation of lignans, a diverse and widely distributed class of secondary plant metabolites exhibiting interesting pharmacological activities and implicated in natural plant defense. However, no detailed information is available about DIR gene family in Medicago truncatula. In this study, a total of 45 DIR genes were identified in M. truncatula. DIR proteins have variability in sequence. Most MtDIR genes have no intron. All MtDIR proteins contain single dirigent domain. A large number of MtDIR genes were expanded via gene duplication, and 37 MtDIR genes were duplicated in tandem. Digital expression data showed that 40% MtDIR genes had a higher expression level in the root. Analysis of RNA-seq and microarray data indicated that more than 30% MtDIR genes were responsive to biotic and/or abiotic treatments. This study will facilitate further studies on DIR family and provide useful clues for functional validation of DIR genes in higher plants.

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Dioecy distributed in 157 flowering plant families and 959 flowering plant genera. Morphological and physiological differences between male and female plants have been studied extensively, but studies of sex-specific genetic diversity are relatively scarce in dioecious plants. In this study, 20 SSR loci were employed to examine the genetic variance of male subpopulations and female subpopulations in Salix viminalis. The results showed that all of the markers were polymorphic (Na = 14.15, He = 0.7566) and workable to reveal the genetic diversity of S. viminalis. No statistically significant difference was detected between male and female subpopulations, but the average genetic diversity of male subpopulations (Na = 7.12, He = 0.7071) and female subpopulations (Na = 7.31, He = 0.7226) were high. Under unfavorable environments (West Liao basin), the genetic diversity between male and female subpopulations was still not significantly different, but the genetic diversity of sexual subpopulations were lower. The differentiation of the ten subpopulations in S. viminalis was moderate (FST = 0.0858), which was conformed by AMOVA that most of genetic variance (94%) existed within subpopulations. Pairwise FST indicated no differentiation between sexual subpopulations, which was accompanied by high long-term migrate between them (M = 0.73~1.26). However, little recent migration was found between sexual subpopulations. Therefore, artificial crossing or/and transplantation by cutting propagation should be carried out so as to increase the migration during the process of ex situ conservation.

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Taking high protein wheat variety 'Beinong 9549' as test material, this paper studied the effects of foliage-spraying different concentration (0, 1.0, 5.0 and 10.0 mmol x L(-1)) proline on the growth and heavy metal uptake of wheat seedlings under cadmium stress. Under the stress of 1.0 mmol x L(-1) of CdCl2, the root length, plant height and dry mass, leaf chlorophyll a and b and carotenoid contents of the seedlings decreased significantly by 24.0%, 15.0%, 27.5%, 23.3%, 6.7% and 30.8%, respectively, the leaf superoxide dismutase (SOD) activity decreased by 18.4%, the leaf proline, ascorbic acid and malondialdehyde (MDA) contents and the membrane permeability increased significantly by 78.6%, 31.5%, 17.9% and 24.8%, respectively, the leaf peroxidase (POD) activity was 2.4 folds higher, and the Cu uptake was promoted while the Zu absorption was inhibited, compared with the control. With the increasing concentration of sprayed proline, the root length, plant height and dry mass, and leaf chlorophyll a and b and carotenoid contents increased gradually to the levels of the control, the leaf proline and ascorbic acid contents and the leaf SOD activity increased, the leaf soluble protein content decreased after an initial increase, the leaf POD activity, MDA content and membrane permeability decreased, and the Zn accumulation increased while the Cd and Cu accumulation decreased. In sum, foliage-spraying proline could alleviate the cadmium stress on the growth of wheat seedlings, and spraying 5.0-10.0 mmol x L(-1) of proline could obtain the best effect.

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