Transcriptomic profiling of the cold stress and recovery responsiveness of two contrasting Guizhou HE rice genotypes.

BACKGROUND: At the seed germination stage, rice is sensitive to cold stress, which adversely affects its growth and development. Guizhou HE rice comprises several different landraces, most of which are cold tolerant. OBJECTIVE: To identify differentially expressed genes and molecular mechanism underlying the cold tolerance of Guizhou HE. METHODS: Two Guizhou HE genotypes, AC44 (cold-sensitive) and AC96 (cold-tolerant), which exhibit opposite phenotypes in response to cold treatment at the seed germination stage were used. Comprehensive gene expressions of AC44 and AC96 under 4 °C cold treatment and subsequent recovery conditions were comparatively analyzed by RNA sequencing. RESULTS: Overall, 11,082 and 7749 differentially expressed genes were detected in AC44 and AC96, respectively. Comparative transcriptome analysis demonstrated that, compared with AC44, AC96 presented fewer upregulated and downregulated genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses demonstrated that AC96 presented more upregulated GO terms, especially terms associated with biological processes. However, AC44 presented more terms related to cellular components, mainly chloroplasts. Moreover, DEGs related to the auxin signaling pathway (including ARF and IAA family members) and transcription factors (including members of the F-box, bZIP, basic helix-loop-helix [bHLH], and MYB-like transcription factor families) were found to be expressed specifically in AC96; thus, these DEGs may be responsible for the cold tolerance of AC96. CONCLUSIONS: These findings present information about the cold tolerance mechanism of Guizhou HE rice at the germination stage, providing valuable resources and candidate genes for breeding cold-tolerant rice genotypes.

Comparative cellular, physiological and transcriptome analyses reveal the potential easy dehulling mechanism of rice-tartary buckwheat (Fagopyrum Tararicum).

BACKGROUND: Tartary buckwheat has gained popularity in the food marketplace due to its abundant nutrients and high bioactive flavonoid content. However, its difficult dehulling process has severely restricted its food processing industry development. Rice-tartary buckwheat, a rare local variety, is very easily dehulled, but the cellular, physiological and molecular mechanisms responsible for this easy dehulling remains largely unclear. RESULTS: In this study, we integrated analyses of the comparative cellular, physiological, transcriptome, and gene coexpression network to insight into the reason that rice-tartary buckwheat is easy to dehull. Compared to normal tartary buckwheat, rice-tartary buckwheat has significantly brittler and thinner hull, and thinner cell wall in hull sclerenchyma cells. Furthermore, the cellulose, hemicellulose, and lignin contents of rice-tartary buckwheat hull were significantly lower than those in all or part of the tested normal tartary buckwheat cultivars, respectively, and the significant difference in cellulose and hemicellulose contents between rice-tartary buckwheat and normal tartary buckwheat began at 10 days after pollination (DAP). Comparative transcriptome analysis identified a total of 9250 differentially expressed genes (DEGs) between the rice- and normal-tartary buckwheat hulls at four different development stages. Weighted gene coexpression network analysis (WGCNA) of all DEGs identified a key module associated with the formation of the hull difference between rice- and normal-tartary buckwheat. In this specific module, many secondary cell wall (SCW) biosynthesis regulatory and structural genes, which involved in cellulose and hemicellulose biosynthesis, were identified as hub genes and displayed coexpression. These identified hub genes of SCW biosynthesis were significantly lower expression in rice-tartary buckwheat hull than in normal tartary buckwheat at the early hull development stages. Among them, the expression of 17 SCW biosynthesis relative-hub genes were further verified by quantitative real-time polymerase chain reaction (qRT-PCR). CONCLUSIONS: Our results showed that the lower expression of SCW biosynthesis regulatory and structural genes in rice-tartary buckwheat hull in the early development stages contributes to its easy dehulling by reducing the content of cell wall chemical components, which further effects the cell wall thickness of hull sclerenchyma cells, and hull thickness and mechanical strength.

Diagnostic ability of 3-dimensional contrast-enhanced MR angiography in identifying vertebral basilar artery stenosis.

BACKGROUND: Vertebral-basilar artery stenosis is associated with posterior circulation infarction. So correct detection of vertebral basilar artery stenosis is very important. Studies concerning the sensitivity and specificity of 3-dimensional contrast enhanced MR angiography (3D-CE-MRA) in detecting vertebral basilar artery stenosis is generally lacking. METHODS: Retrospectively reviewed the imagines of consecutive one hundred and forty-nine Chinese patients with ischemic stroke or vertigo/dizziness who underwent 3D-CE-MRA and DSA. DSA and CE-MRA images were studied separately and to determine the presence of mild, moderate, or severe stenosis of the vertebral-basilar arteries. Analysis combined with vascular origin image was applied when evaluating the vertebral artery origin stenosis. Sensitivity, specificity, positive and negative predictive values, and the accuracy of 3D-CE-MRA in detecting and grading of vertebral-basilar artery stenosis were calculated. RESULTS: Compared with DSA, sensitivity, specificity and accuracy of 3D-CE-MRA in detecting of vertebral artery origin ≥70% stenosis or occlusion was 97.1%, 77.4% and 81.9%, but diagnostic consistency was poor (K=0.59); Analysis combined with vascular origin images, the specificity (97.8%), accuracy (92.9%) and consistency (K=0.826) was significantly improved. CONCLUSIONS: 3D-CE-MRA is a sensitive and noninvasive technique for the detection of vertebral artery origin stenosis. Furthermore, analysis combined with vascular origin image would improve the diagnostic accuracy.

Assessment of bilateral cerebral peduncular infarction: Magnetic resonance imaging, clinical features, and prognosis.

BACKGROUND: Bilateral cerebral peduncular infarction (BCPI) is an extremely rare neurological disorder, and related literature is scarce. This study investigated the clinical manifestations, magnetic resonance imaging (MRI) features and prognosis of BCPI. METHOD: We retrospectively reviewed the clinical features, MRI and magnetic resonance angiography manifestations, and prognosis of 14 patients with BCPI, confirmed by diffusion-weighted MRI from 5050 cerebral infarction patients at our medical center from January 2007 to June 2013. RESULT: Eleven of the 14 (78.6%) patients had quadriplegia and 9 (64.3%) had decreased consciousness. At the most severe stage, the National Institutes of Health Stroke Scale scores ranged from grades 4 to 26 (mean grade, 18.9). Eleven (78.6%) cases were caused by large artery atherosclerosis. Besides the bilateral cerebral peduncle, the pons (85.7%) and cerebellum (42.9%) were the other infarct locations. Twelve (85.7%) patients had vertebrobasilar artery occlusion or severe stenosis, and 12 (85.7%) did not have collateral patency of the posterior cerebral artery. Thirteen (92.9%) patients had poor prognosis and 9 of them died. OCCLUSION: BCPI is a very rare disorder and associated with severe vertebrobasilar artery stenosis or occlusion without collateral patency of the posterior communicating artery. It has a very poor prognosis.