马占相思 (Acacia mangium)与湿地松 (Pinus elliotii)人工林枯落物层的水文生态功能

分析了马占相思与湿地松人工林枯落物的蓄积量、年凋落量及凋落动态、枯落物层对大气降水的截留、以及枯落物抑制土壤水分蒸发和阻滞径流的效应.结果表明①15龄的马占相思林枯落物蓄积量32.3t/hm2,年凋落量11.14t/hm2,最大持水率253.7%,最大持水量28.26t/hm2;15龄的湿地松林枯落物蓄积量18.7t/hm2,年凋落量7.30t/hm2,最大持水率216.7%,最大持水量15.82hm2;②2种林分对大气降水的截留率分别为15.9%和11.7%,截留率随1次降水降水量(>10mm)的增加而减少;③2～4cm枯落物覆盖下不同含水量的土壤水分蒸发比无覆盖的土壤减少18.2%～78.3%,枯落物层减少土壤水分蒸发的效应随枯落物层厚度和土壤含水量的增大而增加;④2种枯落物对径流流出时间的阻滞效应随径流深(<3mm)和坡度的增加而减小,随枯落物层厚度的增加呈直线增加.通过与部分其它森林类型枯落物层水文生态功能比较,认为马占相思与湿地松林枯落物层具有较为优越的水文生态功能.     

Highlights of genetics research over the past four decades in China

正The year of 2018 marks China's 40th anniversary of the reform and opening up. Coincidently, this year is also the 40th anniversary of Genetics Society of China (GSC), one of the largest academic organizations in China. In October of 1978, GSC was formally established in Nanjing, ushering a new era of genetics research in China, and its mission is to promote genetics research and education.Genetics focuses on the study of genes, genetic variations, and heredity in living organisms. It has permeated every field of     

AhSSK1, a novel SKP1-like protein that interacts with the S-locus F-box protein SLF

The S-locus F-box (SLF/SFB) protein, recently identified as the pollen determinant of S-RNase-based self-incompatibility (SI) in Solanaceae, Scrophulariaceae and Rosaceae, has been proposed to serve as the subunit of an SCF (SKP1-CUL1-F-box) ubiquitin ligase and to target its pistil counterpart S-RNase during the SI response. However, the underlying mechanism is still in dispute, and the putative SLF-binding SKP1-equivalent protein remains unknown. Here, we report the identification of AhSSK1, Antirrhinum hispanicumSLF-interacting SKP1-like1, using a yeast two-hybrid screen against a pollen cDNA library. GST pull-down assays confirmed the SSK1-SLF interaction, and showed that AhSSK1 could connect AhSLF to a CUL1-like protein. AhSSK1, despite having a similar secondary structure to other SKP1-like proteins, appeared quite distinctive in sequence and unique in a phylogenetic analysis, in which no SSK1 ortholog could be predicted in the sequenced genomes of Arabidopsis and rice. Thus, our results suggest that the pollen-specific SSK1 could be recruited exclusively as the adaptor of putative SCF(SLF) in those plants with S-RNase-based SI, providing an important clue to dissecting the function of the pollen determinant.     

Identification of a canonical SCFSLF complex involved in S-RNase-based self-incompatibility of Pyrus (Rosaceae)

S-RNase-based self-incompatibility (SI) is an intraspecific reproductive barrier to prevent self-fertilization found in many species of the Solanaceae, Plantaginaceae and Rosaceae. In this system, S-RNase and SLF/SFB (S-locus F-box) genes have been shown to control the pistil and pollen SI specificity, respectively. Recent studies have shown that the SLF functions as a substrate receptor of a SCF (Skp1/Cullin1/F-box)-type E3 ubiquitin ligase complex to target S-RNases in Solanaceae and Plantaginaceae, but its role in Rosaceae remains largely undefined. Here we report the identification of two pollen-specific SLF-interacting Skp1-like (SSK) proteins, PbSSK1 and PbSSK2, in Pyrus bretschneideri from the tribe Pyreae of Rosaceae. Both yeast two-hybrid and pull-down assays demonstrated that they could connect PbSLFs to PbCUL1 to form a putative canonical SCF^SLF (SSK/CUL1/SLF) complex in Pyrus. Furthermore, pull-down assays showed that the SSK proteins could bind SLF and CUL1 in a cross-species manner between Pyrus and Petunia. Additionally, phylogenetic analysis revealed that the SSK-like proteins from Solanaceae, Plantaginaceae and Rosaceae form a monoclade group, hinting their shared evolutionary origin. Taken together, with the recent identification of a canonical SCF^SFB complex in Prunus of the tribe Amygdaleae of Rosaceae, our results show that a conserved canonical SCF^SLF/SFB complex is present in Solanaceae, Plantaginaceae and Rosaceae, implying that S-RNase-based self-incompatibility shares a similar molecular and biochemical mechanism.     

2019新型冠状病毒信息库

2019年12月在中国武汉开始爆发的新型肺炎已造成全球25个国家/地区的31516人感染、638人死亡(截止2020年2月7日16时),引起该肺炎的病毒被世界卫生组织命名为2019新型冠状病毒(2019-nCoV)。为促进2019-nCoV数据共享应用并及时向全球公众提供病毒的相关信息,国家生物信息中心(CNCB)/国家基因组科学数据中心(NGDC)建立了2019新型冠状病毒信息库(2019nCoVR,https://bigd.big.ac.cn/ncov)。该信息库整合了来自德国全球流感病毒数据库、美国国家生物技术信息中心、深圳(国家)基因库、国家微生物科学数据中心及CNCB/NGDC等机构公开发布的2019-nCoV核苷酸和蛋白质序列数据、元信息、学术文献、新闻动态、科普文章等信息,开展了不同冠状病毒株的基因组序列变异分析并提供可视化展示。同时,2019nCoVR无缝对接CNCB/NGDC的相关数据库,提供新测序病毒株系的基因组原始测序数据、组装后序列的在线汇交、管理与共享、国际数据库同步发布等数据服务。本文对2019nCoVR数据汇交、管理、发布及使用等进行全面阐述,以方便用户了解该信息库各项功能及数据状况,为加速开展病毒的分类溯源、变异演化、快速检测、药物研发以及新型肺炎的精准预防与治疗等研究提供重要基础。     

On the origin of SARS-CoV-2——The blind watchmaker argument

正In the comparison with SARS-CoVof 2003, SARS-CoV-2 is extremely well adapted to the human populations and its adaptive shift from the animal host to humans must have been even more extensive. By the blind watchmaker argument, such an adaptive shift can only happen prior to the onset of the current pandemic and with the aid of step-by-step selection.     

Identification of a ubiquitin-binding structure in the S-locus F-box protein controlling S-RNase-based self-incompatibility

In flowering plants,self-incompatibility(SI) serves as an important intraspecific reproductive barrier to promote outbreeding.In species from the Solanaceae,Plantaginaceae and Rosaceae,S-RNase and SLF(S-locus F-box) proteins have been shown to control the female and male specificity of SI,respectively.However,little is known about structure features of the SLF protein apart from its conserved F-box domain.Here we show that the SLF C-terminal region possesses a novel ubiquitin-binding domain(UBD) structure conserved among the SLF protein family.By using an ex vivo system of Nicotiana benthamiana,we found that the UBD mediates the SLF protein turnover by the ubiquitin—proteasome pathway.Furthermore,we detected that the SLF protein was directly involved in S-RNase degradation.Taken together,our results provide a novel insight into the SLF structure and highlight a potential role of SLF protein stability and degradation in S-RNase-based self-incompatibility.