| Boron(B) is an essential micronutrient for all vascular plants, yeast, bacteria and some species of green algae, and its physiological function involves the structure of plant cell wall, cell membrane stability and function, phenolic metabolism, nitrogen fixation, pollen germination and pollen tube elongation. Oilseed rape(Brassica napus L.) is one of the main oil crops in China, which need much B and showed more sensitive to low soil boron availability. In this study, a B-efficient cultivar Qingyou10 and a B-inefficient cultivar Westar10 screened previously were used to study the transcriptional profile of root, juvenile leaves and old leaves of Qingyou10 and Westar10 at low B(0.25 μM) and normal B(25 μM) at the seedling stage to reveal the differential expression genes(DEGs) and the genes network response to B deficiency of B-efficient and-inefficient cultivars and digging the key genes for B efficiency in oilseed rape. The main results are as follow:1. A total of 9858 differential expression genes(DEGs) were detected in roots(R), juvenile leaves(JL) and old leaves(OL) of Qingyou10(QY10) and Westar10(W10) at low B as compared with normal B. The sequences in number of DEGs were as follow: QY10 > W10; R > OL > JL. 3408, 1482 and 1364 DEGs were detected in R, JL and OL of QY10, respectively; and among them 193 DEGs were detected co-existed in all the three tissues. 2053, 1054 and 1182 DEGs were detected in R, JL and OL of W10, respectively, and 77 DEGs were found co-existed in all the three tissues. Moreover, 25 DEGs were detected in R, JL and OL of both QY10 and W10 at low B, and all of them showed up-regulated under B deciency.2. GO analysis of these DEGs demonstated that most of them were located in membrane(2.6%), nucleus(1.3%) and cell wall(1.1%) and the molecular functions of these DEGs involved in catalyze activity(7.9%), oxidoreductase activity(4.2%), transferase activity(3.4%). Biological processes of these DEGs involved in metabolic process(3.6%), defense response(1.6%), metal ion transport(1.0%) and so on. KEGG pathway involved in carbohydrates metabolism(363 DEGs enriched), oxidative phosphorylation(175 DEGs enriched), glycolysis(141 DEGs enriched), nitrogen metabolism(154 DEGs enriched) and so on.3. A network for cell wall biosynthesis and metabolism and its regulated genes of oilseed rape under B deficiency was established based on the detected DEGs of B-efficient and-inefficient culitivars at low and normal B. It showed that the substrates of cell wall synthesis, the modification of primary and secondary cell walls of B-efficient and –inefficient cultivars could be affected under B deficiency, and that of QY10 were affected more seriously than that of W10. Some seed genes for cell wall synthesis and metabolism at low B were predicted by Cytoscape software, which were two genes for pectatelyase(Gene ID: Fna000220, Fna041412), two genes for expansins(Gene ID: Fna070546, Fna010670) and three genes for pectinesterase(Gene ID: Fna024381, Fna069009, Fna075584) genes respectively.4. A network for cell membrane biosynthesis and metabolism and its regulated genes of oilseed rape under B deficiency was established based on the detected DEGs of B-efficient and-inefficient culitivars at low and normal B. It showed that membrane functions and integrity of two cultivars could be influenced under B deficiency, and that of W10 would be affected more seriously than that of QY10. An annexin gene(Gene ID: Fna076501) was predicted to be the seed gene for cell membrane biosynthesis and metabolism under B deficiency by Cytoscape software.5. The expression pattern of WRKY family genes under B deficiency in a plant were described based on the detected DEGs of B-efficient and-inefficient culitivars at low and normal B. An interactive genes network of WRKY6 showed that WRKY6 could regulate the plant resoponses to B deficiency through the influences of sugar transporter, selenium-binding protein etc in oilseed rape.6. Six Bn BOR1 s were detected and among them, gene expression level of Bna C03g72490 D were higher than other five Bn BOR1 s whether at low or normal B conditions; The gene expressions of Bna A05g00740 D and Bna C04g00350 D were both up-regulated in the root of QY10 and W10 under B deficiency, and gene expression level of QY10 were less than that of W10. Five Bn NIP5;1s were detected and among them, Bna A02g22030 D and Bna C02g29210 D were up-regulated significantly under B deficiency in the root of QY10 and W10, and gene expression level of W10 were higher than that of QY10. Moreover, the gene expression levels of Bn NIP5;1s were higher than that of Bn BOR1 s of B –efficient and-inefficient cultivars under B deficiency. Four Bn NIP6;1 were detected and among them, Bna C06g40240 D were predicted to be the seed gene. |
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