High-integrity Pueraria montana var. lobata genome and population analysis revealed the genetic diversity of Pueraria genus.

Pueraria montana var. lobata (P. lobata) is a traditional medicinal plant belonging to the Pueraria genus of Fabaceae family. Pueraria montana var. thomsonii (P. thomsonii) and Pueraria montana var. montana (P. montana) are its related species. However, evolutionary history of the Pueraria genus is still largely unknown. Here, a high-integrity, chromosome-level genome of P. lobata and an improved genome of P. thomsonii were reported. It found evidence for an ancient whole-genome triplication and a recent whole-genome duplication shared with Fabaceae in three Pueraria species. Population genomics of 121 Pueraria accessions demonstrated that P. lobata populations had substantially higher genetic diversity, and P. thomsonii was probably derived from P. lobata by domestication as a subspecies. Selection sweep analysis identified candidate genes in P. thomsonii populations associated with the synthesis of auxin and gibberellin, which potentially play a role in the expansion and starch accumulation of tubers in P. thomsonii. Overall, the findings provide new insights into the evolutionary and domestication history of the Pueraria genome and offer a valuable genomic resource for the genetic improvement of these species.

Comparative plastomes of Pueraria montana var. lobata (Leguminosae: Phaseoleae) and closely related taxa: insights into phylogenomic implications and evolutionary divergence.

BACKGROUND: Pueraria montana var. lobata (kudzu) is an important food and medicinal crop in Asia. However, the phylogenetic relationships between Pueraria montana var. lobata and the other two varieties (P. montana var. thomsonii and P. montana var. montana) remain debated. Although there is increasing evidence showing that P. montana var. lobata adapts to various environments and is an invasive species in America, few studies have systematically investigated the role of the phylogenetic relationships and evolutionary patterns of plastomes between P. montana var. lobata and its closely related taxa. RESULTS: 26 newly sequenced chloroplast genomes of Pueraria accessions resulted in assembled plastomes with sizes ranging from 153,360 bp to 153,551 bp. Each chloroplast genome contained 130 genes, including eight rRNA genes, 37 tRNA genes, and 85 protein-coding genes. For 24 newly sequenced accessions of these three varieties of P. montana, we detected three genes and ten noncoding regions with higher nucleotide diversity (π). After incorporated publically available chloroplast genomes of Pueraria and other legumes, 47 chloroplast genomes were used to construct phylogenetic trees, including seven P. montana var. lobata, 14 P. montana var. thomsonii and six P. montana var. montana. Phylogenetic analysis revealed that P. montana var. lobata and P. montana var. thomsonii formed a clade, while all sampled P. montana var. montana formed another cluster based on cp genomes, LSC, SSC and protein-coding genes. Twenty-six amino acid residues were identified under positive selection with the site model. We also detected six genes (accD, ndhB, ndhC, rpl2, rpoC2, and rps2) that account for among-site variation in selective constraint under the clade model between accessions of the Pueraria montana var. lobata clade and the Pueraria montana var. montana clade. CONCLUSION: Our data provide novel comparative plastid genomic insights into conservative gene content and structure of cp genomes pertaining to P. montana var. lobata and the other two varieties, and reveal an important phylogenetic clue and plastid divergence among related taxa of P. montana come from loci that own moderate variation and underwent modest selection.

Comparative physiology and transcriptome analysis allows for identification of lncRNAs imparting tolerance to drought stress in autotetraploid cassava.

BACKGROUND: Polyploidization, pervasive among higher plant species, enhances adaptation to water deficit, but the physiological and molecular advantages need to be investigated widely. Long non-coding RNAs (lncRNAs) are involved in drought tolerance in various crops. RESULTS: Herein, we demonstrate that tetraploidy potentiates tolerance to drought stress in cassava (Manihot esculenta Crantz). Autotetraploidy reduces transpiration by lesser extent increasing of stomatal density, smaller stomatal aperture size, or greater stomatal closure, and reducing accumulation of H2O2 under drought stress. Transcriptome analysis of autotetraploid samples revealed down-regulation of genes involved in photosynthesis under drought stress, and less down-regulation of subtilisin-like proteases involved in increasing stomatal density. UDP-glucosyltransferases were increased more or reduced less in dehydrated leaves of autotetraploids compared with controls. Strand-specific RNA-seq data (validated by quantitative real time PCR) identified 2372 lncRNAs, and 86 autotetraploid-specific lncRNAs were differentially expressed in stressed leaves. The co-expressed network analysis indicated that LNC_001148 and LNC_000160 in autotetraploid dehydrated leaves regulated six genes encoding subtilisin-like protease above mentioned, thereby result in increasing the stomatal density to a lesser extent in autotetraploid cassava. Trans-regulatory network analysis suggested that autotetraploid-specific differentially expressed lncRNAs were associated with galactose metabolism, pentose phosphate pathway and brassinosteroid biosynthesis, etc. CONCLUSION: Tetraploidy potentiates tolerance to drought stress in cassava, and LNC_001148 and LNC_000160 mediate drought tolerance by regulating stomatal density in autotetraploid cassava.

Facilitative effect of glycine on regulation of baroreflex in the hypothalamic paraventricular nucleus of conscious rats / 生理学报

The hypothalamic paraventricular nucleus (PVN) is a central site for integration of the endocrine system and the autonomic nervous system. Despite a number of studies have pointed out the importance of the PVN in the central regulation of cardiovascular functions, the chemical mediators in the PVN responsible for mediating baroreflex are not well understood. In the present study, we used the conscious rats to investigate the possible involvement of glycine (Gly) in PVN in the central regulation of baroreflex induced by intravenous injection of phenylephrine (0.8 mug/0.04 mL, in 3 min). Then, the microdialysis sampling was performed in the PVN and the concentration of Gly in the microdialysate was measured by high performance liquid chromatography (HPLC) combined with electrochemical techniques, and mean arterial pressure (MAP) and heart rate (HR) were recorded simultaneously. Injection of phenylephrine elicited a significant increase (P<0.01) in MAP from the baseline of (99.5+/-14.2) mmHg to the maximum of (149.8+/-19.5) mmHg and a decrease (P<0.01) in HR from the baseline of (400.8+/-33.1) beats/min to the minimum of (273.4+/-40.8) beats/min, respectively. Synchronously, the injection of phenylephrine increased the level of Gly in the microdialysate from the PVN to (162.9+/-27.3)% of the basal level (P<0.05). Perfusion of strychnine (100 mumol/L), an antagonist of Gly receptor, into the PVN enhanced the pressor response and attenuated the bradycardic response during the baroreflex, resulting in a decrease in baroreflex sensitivity (P<0.001). Whereas, the perfusion of Gly (1 mmol/L) into the PVN did not affect the pressor response but enhanced the bradycardic response during the baroreflex, resulting in an increase in baroreflex sensitivity (P<0.001). These results suggest that endogenous Gly in the PVN may act via strychnine-sensitive Gly receptor to produce a facilitative effect on baroreflex.

Cardiovascular change induced by central hypertonic saline are accompanied by GABA release in awake rats / 中国应用生理学杂志

<p><b>AIM</b>To investigate the possible involvement of gamma-aminobutyric acid (GABA) in the paraventricular nucleus (PVN) in cardiovascular responses induced by central salt loading.</p><p><b>METHODS</b>Direct perfusion into PVN region with hypertonic saline (0.6 mol/L) was performed in conscious rats by using an in vivo brain microdialysis technique. Then, the extracellular concentration of GABA in the PVN region was measured by microdialysis and high performance liquid chromatography (HPLC) techniques, and the blood pressure (BP) and heart rate (HR) were with recorded simultaneously. Bicuculline (an antagonist of GABAA receptor) or saclofen (an antagonist of GABAB receptor) were coperfused hypertonic saline into PVN region, then the cardiovascular responses were examined.</p><p><b>RESULTS</b>(1) The local perfusion of 0.6 mol/L saline elicited significant increases on BP and HR (P < 0.01). In addition, perfusion of 0.6 mol/L saline increased the extracellular GABA levels in the PVN region, which reached 561.96% +/- 173.96% (P < 0.05) of the basal level. (2) Bicuculline or salcofen significantly attenuated the in-response of BP (P < 0.01, respectively), whereas the antagonists did not influence the response of HR induced by hypertonic saline.</p><p><b>CONCLUSION</b>Local perfusion of hypertonic saline in the PVN region elicits a local release of GABA, which may act via GABA(A) and GABA(B) receptors to produce pressor response.</p>

Changes of glutamate and taurine released in the medial vestibular nucleus following acute hypotension / 生理学报

In order to understand whether some special amino acids in the medial vestibular nucleus (MVN) of rats are involved in the regulation of blood pressure, we used microdialysis technique and high performance liquid chromatography (HPLC) to measure the changes of glutamate and taurine in this central area. Acute hypotension was induced by hemorrhage from the femoral artery. It was observed that the basal release of glutamate and taurine in the MVN was stable about 90 min after the beginning of microdialysis. The basal release of glutamate was (18.96 +/- 0.27) pmol/sample (8 mul), and that of taurine was (7.73 +/- 0.05) pmol/sample (8 mul). Glutamate release increased (P<0.05) and taurine release reduced (P<0.05) in the MVN in the hemorrhage-induced acute hypotensive rats. Nevertheless, these changes were not observed in the hemorrhage-induced acute hypotensive rats which were pretreated by infusing 2% lidocaine into the middle ear or 100 mg arsanilic acid into the tympanic cavity. These results suggest that the hemorrhage-induced acute hypotention can influence the activity of the neurons in the MVN by the afferent impulses from vestibular organ, and that some special amino acid transmitters in the MVN are involved in this process.