A novel case of autogamy and cleistogamy in Dendrobium wangliangii: A rare orchid distributed in the dry‐hot valley

Dendrobium wangliangii is an epiphytic orchid distributed in the Jinshajiang dry‐hot valley in Luquan County, Yunnan Province, China. Most Dendrobium spp. typically have a low fruit set, but this orchid shows a higher fruit set under natural conditions despite the lack of effective pollinators. The pollination biology of the critically endangered D. wangliangii was investigated in this study. A fruit set rate of 33.33 ± 4.71% was observed after bagging treatment in 2017 and a high fruit set rate (65.72 ± 4.44% in 2011; 50.79 ± 5.44% in 2017) was observed under natural conditions, indicating that D. wangliangii is characterized by spontaneous self‐pollination. The anther cap blocked the growing pollinium; thus, the pollinium slid down and reached the stigmatic cavity, leading to autogamous self‐pollination. Specifically, 51.50% of 162 unopened flowers (total 257 flowers) of this Dendrobium species under extreme water‐deficit conditions developed into fruits, suggesting the presence of cleistogamy in D. wangliangii. Here, cleistogamy may represent the primary mode of pollination for this orchid. Spontaneous self‐pollination and specific cleistogamous autogamy could represent major adaptions to the drought and pollinator‐scarce habitat in the Jinshajiang dry‐hot valley.     

DDX19 Inhibits Type I Interferon Production by Disrupting TBK1-IKKε-IRF3 Interactions and Promoting TBK1 and IKKε Degradation

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Mafb and c-Maf Have Prenatal Compensatory and Postnatal Antagonistic Roles in Cortical Interneuron Fate and Function

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POLLEN STERILITY,a novel suppressor of cell division,is required for timely tapetal programmed cell death in rice

Science China Life Sciences - Timely programmed cell death (PCD) of the tapetum supplying nutrients to microspores is a prerequisite for normal pollen development. Here we identified a unique...     

Advancements in endometrial epithelial stem cell research

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LncDACH1 promotes mitochondrial oxidative stress of cardiomyocytes by interacting with sirtuin3 and aggravates diabetic cardiomyopathy

Science China Life Sciences - Diabetic cardiomyopathy (DCM) is a common complication in diabetic patients. The molecular mechanisms of DCM remain to be fully elucidated. The intronic long noncoding...     

Ancient genomes reveal the genetic inheritance and recent introgression in Chinese indigenous pigs

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Fruit and vegetable consumption,cardiovascular disease,and all-cause mortality in China

Science China Life Sciences - Evidence about the response patterns of fruit and vegetable consumption with the risk of cardiovascular disease (CVD) and all-cause mortality was inconsistent. These...     

Metabolic engineering strategies of de novo pathway for enhancing 2′-fucosyllactose synthesis in Escherichia coli

2′-Fucosyllactose (2′-FL), one of the most abundant human milk oligosaccharides (HMOs), is used as a promising infant formula ingredient owing to its multiple health benefits for newborns. However, limited availability and high-cost preparation have restricted its extensive use and intensive research on its potential functions. In this work, a powerful Escherichia coli cell factory was developed to ulteriorly increase 2′-FL production. Initially, a modular pathway engineering was strengthened to balance the synthesis pathway through different plasmid combinations with a resulting maximum 2′-FL titre of 1.45 g l⁻¹. To further facilitate the metabolic flux from GDP-l -fucose towards 2′-FL, the CRISPR-Cas9 system was utilized to inactivate the genes including lacZ and wcaJ, increasing the titre by 6.59-fold. Notably, the co-introduction of NADPH and GTP regeneration pathways was confirmed to be more conducive to 2′-FL formation, achieving a 2′-FL titre of 2.24 g l⁻¹. Moreover, comparisons of various exogenous α1,2-fucosyltransferase candidates revealed that futC from Helicobacter pylori generated the highest titre of 2′-FL. Finally, the viability of scaled-up production of 2′-FL was evidenced in a 3 l bioreactor with a maximum titre of 22.3 g l⁻¹ 2′-FL and a yield of 0.53 mole 2′-FL mole⁻¹ lactose.     

Substrate availability regulates the suppressive effects of Canada goldenrod invasion on soil respiration

基质有效性调节加拿大一枝黄花入侵对土壤呼吸的抑制作用 外来植物入侵不仅会降低河边近岸湿地生态系统植被多样性,而且会改变湿地生态系统的地下碳过程。外来入侵植物加拿大一枝黄花(Solidago canadensis L.)已广泛入侵我国东南部地区,但加拿大一枝黄花入侵对入侵地生态系统地下土壤碳循环过程的影响却知之甚少。本研究通过野外原位观测实验和温室模拟入侵实验,探究外来植物加拿大一枝黄花入侵对入侵地土壤呼吸的影响规律及其驱动因素。野 外原位观测实验开展于2018年7月21日至12月15日,期间每周测定样地土壤呼吸。温室模拟入侵实验开展于2019年7月15日至12月15日,期间每月1日与15日上午测定土壤呼吸、自养呼吸和异养呼吸。土壤呼吸、自养呼吸和异养呼吸通过静态箱结合深埋根系隔离法测定。野外原位观测实验和温室模拟入侵实验结果均显示,加拿大一枝黄花的入侵降低了土壤二氧化碳的排放通量。加拿大一枝黄花入侵对土壤呼吸的抑制作用可能归因于其入侵引起的土壤可利用底物质量与数量的变化,表明外来入侵植物加拿大一枝黄花可通过改变植物释放基质以及与本地植物和/或土壤微生物争夺土壤有效基质而影响土壤碳循环。这些研究结果对于评估外来入侵植物对入侵地地下碳动态的影响以及对全球变暖的贡献具有重要意义。