A polygalacturonase gene OsPG1 modulates water homeostasis in rice

A dynamic plant architecture is the basis of plant adaptation to changing environments.Although many genes regulating leaf rolling have been identified,genes directly associated with water homeostasis are largely unknown.Here,we isolated a rice mutant,dynamic leaf rolling 1(dlr1),characterized by‘leaf unfolding in the morning-leaf rolling at noon-leaf unfolding in the evening’during a sunny day.Water content was decreased in rolled leaves and water sprayed on leaves caused reopening,indicating that in vivo water deficiency induced the leaf rolling.Map-based cloning and expression tests demonstrated that an A1400G single base mutation in Oryza sativa Polygalacturonase 1(OsPG1)/PHOTO-SENSITIVE LEAF ROLLING 1(PSL1)was responsible for the dynamic leaf rolling phenotype in the dlr1 mutant.OsPG1 encodes a polygalacturonase,one of the main enzymes that degrade demethylesterified homogalacturonans in plant cell walls.OsPG1 was constitutively expressed in various tissues and was enriched in stomata.Mutants of the OsPG1 gene exhibited defects in stomatal closure and decreased stomatal density,leading to reduced transpiration and excessive water loss under specific conditions,but had normal root development.Further analysis revealed that mutation of OsPG1 led to reduced pectinase activity in the leaves and increased demethylesterified homogalacturonans in guard cells.Our findings reveal a mechanism by which OsPG1 modulates water homeostasis to control dynamic leaf rolling,providing insights for plants to adapt to environmental variation.

Preparation of conductive and transparent dipeptide hydrogels for wearable biosensor

Conductive and transparent dipeptide hydrogels are desirable building blocks to prepare soft electronic devices and wearable biosensors due to their excellent biocompatibility,multi-functionality,and physiochemical properties similar to those of body tissues.However,the preparation of such hydrogels featuring high conductivity and transparency is a huge challenge because of the hydrophobic feature of conductive additives making the doping process difficult.To overcome this issue,hydrophilic conductive polydopamine(PDA)-doped polypyrrole(PPy)nanoparticles are introduced into the dipeptide hydrogel networks to form conductive nanofibrils in situ to achieve a good level of hydrophilic templating of the hydrogel networks.This tech-nique creates a complete conductive network and allows visible light to pass through.The strategy proposed herein not only endows the dipeptide hydrogel with good conductivity and high transparency,but also provides a great potential application of conductive dipeptide hydrogels for body-adhered signal detection,as evidenced by the experimental data.

采集策略对叶附生苔类植物发现概率及物种多样性的重要性

叶附生苔类植物主要生长在热带和亚热带常绿阔叶林维管植物叶片的表面,是苔藓植物中较为复杂的一个类群,特殊的生理生态特性使其在成为气候变化指示类群方面的潜力很大。为了探究采集者的经验及采样强度是否显著影响叶附生苔的发现概率及物种多样性,本研究在乌岩岭国家级自然保护区对叶附生苔开展了系统的采集和比较研究,以期为我国其他地区开展叶附生苔类植物的调查和研究提供经验和方法支持。通过4位具有不同采集经验的采集者在规定的时间(每人每次30 min)和区域(铁炉基至黄家岱)内对叶附生苔进行3次重复采集,分析不同采集者所采集到的含有叶附生苔的叶片数及所获得的物种多样性之间的差异。结果显示,4位采集者共采集叶附生苔类植物5科11属36种,并新增1种首次发现附生于叶片的种类(南溪苔Makinoa crispata)。采集者经验对叶附生苔的发现概率影响不显著,但对叶附生苔的物种多样性,尤其是一般种和优势种的多样性具有显著影响,推测这一差异主要是由采集者不同的采集策略所导致。同时,本研究结果还表明,叶附生苔的物种多样性随着采样强度的增加而增加,4位采集者共同参与的采样结果体现出较高的采样充分性。本研究结果表明即使针对叶附生苔类植物这一类常被认为采集和鉴定非常困难的类群,如加以必要的采集前的经验培训,即使是非专业的采集人员也足以开展针对叶附生苔类植物的调查。