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Grassland degradation has emerged as a serious socio-economic and ecological problem, endangering both long-term usage and the regional biogeochemical cycle. Climate change and human activities are the two leading factors leading to grassland degradation. However, it is unclear what the degradation level caused by these two factors is. Using the normalized difference vegetation index (NDVI) and coefficient of variation of NDVI (CV NDVI ), the spatial distribution features of grassland degradation or restoration were analyzed in Qilian County in the northeast of the Qinghai–Tibet Plateau. The dominant climate variables affecting NDVI variation were selected through the combination of random forest model and stepwise regression method to improve the residual trend analysis, and on this basis, twelve possible scenarios were established to evaluate the driving factors of different degraded grasslands. Finally, used the Hurst index to forecast the trend of grassland degradation or restoration. The results showed that approximately 55.0% of the grassland had been degraded between 2000 and 2019, and the area of slight degradation (NDVI slope  > 0; CV NDVI (slope)  > 0; NDVI value  > 0.2) accounted for 48.6%. These regions were centered in the northwest of Qilian County. Climate and human activities had a joint impact on grassland restoration or degradation. Human activities played a leading role in grassland restoration, while climate change was primarily a driver of grassland degradation. The regions with slight degradation or re-growing (NDVI slope  > 0; CV NDVI (slope)  > 0), moderate degradation (NDVI slope  < 0; CV NDVI (slope)  > 0), and severe degradation or desertification (NDVI slope  < 0; CV NDVI (slope)  < 0) were dominated by the joint effects of climate and anthropogenic activity accounted for 34.3%, 3.3%, and 1.3%, respectively, of the total grassland area. Grasslands in most areas of Qilian County are forecasted to continue to degrade, including the previously degraded areas, with continuous degradation areas accounting for 54.78%. Accurately identifying the driving factors of different degraded grassland and predicting the dynamic change trend of grassland in the future is the key to understand the mechanism of grassland degradation and prevent grassland degradation. The findings offer a reference for accurately identifying the driving forces in grassland degradation, as well as providing a scientific basis for the policy-making of grassland ecological management.

Relationships between biodiversity and multiple ecosystem functions (that is, ecosystem multifunctionality) are context-dependent. Both plant and soil microbial diversity have been reported to regulate ecosystem multifunctionality, but how their relative importance varies along environmental gradients remains poorly understood. Here, we relate plant and microbial diversity to soil multifunctionality across 130 dryland sites along a 4,000 km aridity gradient in northern China. Our results show a strong positive association between plant species richness and soil multifunctionality in less arid regions, whereas microbial diversity, in particular of fungi, is positively associated with multifunctionality in more arid regions. This shift in the relationships between plant or microbial diversity and soil multifunctionality occur at an aridity level of ∼0.8, the boundary between semiarid and arid climates, which is predicted to advance geographically ∼28% by the end of the current century. Our study highlights that biodiversity loss of plants and soil microorganisms may have especially strong consequences under low and high aridity conditions, respectively, which calls for climate-specific biodiversity conservation strategies to mitigate the effects of aridification. Biodiversity-ecosystem functioning relationships may vary with climate. Here, the authors study relationships of plant and soil microbial diversity with soil nutrient multifunctionality in 130 dryland sites in China, finding a shift towards greater importance of soil microbial diversity in arid conditions.

The plant cell wall is the first physical and defensive barrier against pathogens. The plant cell wall usually undergoes dynamic remodeling as an immune response to prevent infection by pathogens. In this review, we summarize advances on relationship between cell wall and immunity in plants. In particular, we outline current progresses regarding the regulation of the cell wall components, including cellulose, hemicellulose, pectin and lignin, on plant disease resistance. We also discuss the impacts of cell wall-derived cellodextrin, oligogalacturonic acid and xyloglucan/xylan oligosaccharides as potent elicitors or signal molecules to trigger plant immune response. We further propose future studies on dissecting the molecular regulation of cell wall on plant immunity, which have potentials in practical application of crop breeding aiming at improvement of plant disease resistance.

The interest in the application of deep eutectic solvents (DES) as a green solvent has increased rapidly. The application of DES in agro-industrial okara treatment can be developed into industrialization. In order to simplify the degreasing, deproteinization and cellulose extraction steps in the process of pretreating okara cellulose, a new approach to cellulose extraction from okara via one-pot DES treatment is established. Three different complexing agents, choline salts in oxalic acid, in glycerol and in urea are studied in this work. The structure and properties of cellulose nanofibers (CNFs) prepared by high pressure homogenization following pretreatment of okara with anionic systhesized DES are investigated. The effects of different systems on the degree of microfibrillation of okara are analyzed using techniques such as SEM, FTIR, TD and DTG. The results indicate that by pretreating okara with choline chloride–oxalic acid type solvent, CNFs with average diameter of 27 nm are obtained using high pressure homogenization.

Grain size is one of the key determinants of grain yield. Although a number of genes that control grain size in rice (Oryza sativa) have been identified, the overall regulatory networks behind this process remain poorly understood. Here, we report the map-based cloning and functional characterization of the quantitative trait locus GL6, which encodes a plant-specific plant AT-rich sequence- and zinc-binding transcription factor that regulates rice grain length and spikelet number. GL6 positively controls grain length by promoting cell proliferation in young panicles and grains. The null gl6 mutant possesses short grains, whereas overexpression of GL6 results in large grains and decreased grain number per panicle. We demonstrate that GL6 participates in RNA polymerase III transcription machinery by interacting with RNA polymerase III subunit C53 and transcription factor class C1 to regulate the expression of genes involved in rice grain development. Our findings reveal a further player involved in the regulation of rice grain size that may be exploited in future rice breeding.

Hybrid rice breeding for exploiting hybrid vigor, heterosis, has greatly increased grain yield. However, the heterosis-related genes associated with rice grain production remain largely unknown, partly because comprehensive mapping of heterosis-related traits is still labor-intensive and time-consuming. Here, we present a quantitative trait locus (QTL) mapping method, GradedPool-Seq, for rapidly mapping QTLs by whole-genome sequencing of graded-pool samples from F 2 progeny via bulked-segregant analysis. We implement this method and map-based cloning to dissect the heterotic QTL GW3p6 from the female line. We then generate the near isogenic line NIL-FH676:: GW3p6 by introgressing the GW3p6 allele from the female line Guangzhan63-4S into the male inbred line Fuhui676. The NIL-FH676:: GW3p6 exhibits grain yield highly increased compared to Fuhui676. This study demonstrates that it may be possible to achieve a high level of grain production in inbred rice lines without the need to construct hybrids. Developing hybrid rice cultivars requires time consuming random crossing. Here, the authors develop a new next generation sequencing-based quantitative trait locus mapping method to dissect heterotic gene OsMADS1 and demonstrate the feasibility of pyramiding two genes to achieve large heterotic effect.

IntroductionScientific grazing management is of great significance for the ecological health and sustainable use of alpine meadows.MethodsTo explore appropriate management methods of alpine grasslands of the Qinghai-Tibet Plateau degraded by Achnatherum inebrians (Hance) Keng ex Tzvele presence, we studied the effects of different grazing systems on the A. inebrians population, grassland vegetation community traits, soil characteristics and soil microbial community structure for cold- season grazing plus supplementary feeding pasture (CSF) and four-season open public pasture (FOP) in Tianzhu County, Gansu Province.ResultsCompared with FOP, the CSF site showed significantly inhibited reproduction of A. inebrians , especially the crown width, seed yield and number of reproductive branches per plant were as high as 50%, significantly increased the aboveground biomass of edible forage and soil water content by 57% and 43–55%, better soil nutrients, and significantly reduced soil bulk density by 10– 29%. Different grazing systems affected the composition and diversity of soil microbial communities, with a greater effect on fungi than on bacterial flora. The most abundant phyla of bacteria and fungi were Proteobacteria and Ascomycota for CSF (by 30–38% and 24–28%) and for FOP (by 67–70% and 68–73%), and the relative abundance and species of bacterial and fungal genera were greater for CSF than FOP. The α-diversity indexes of fungi were improved, and the β-diversity of fungi was significant difference between CSF and FOP. However, the grazing utilization time was prolonged in FOP, which reduced the diversity and abundance of soil bacteria and increased soil spatial heterogeneity. The use of A. inebrians -type degraded grassland in the cold season, and as a winter supplementary feeding and resting ground, could effectively inhibit expansion of A. inebrians , promote edible forage growth, enhance grassland productivity and community stability, and improve soil structure.DiscussionThe results guide healthy and sustainable utilization of A. inebrians -type degraded grassland in the Qinghai-Tibet Plateau.

The Ideal Plant Architecture 1 (IPA1) transcription factor promotes rice yield and immunity through phosphorylation at its amino acid residue Ser163 as a switch. Although phosphorylated IPA1 mimic, IPA1(S163D), directly targets the promoter of immune response gene WRKY45 , it cannot activate its expression. Here, we identified a co-activator of IPA1(S163D), a RING-finger E3 ligase IPA1 interactor 7 (IPI7), which fine-tunes the transcriptional activity of IPA1 to timely promote plant immunity and simultaneously maintain growth for yield. IPI7 interacts with IPA1 and promotes K29-polyubiquitination of IPA1 in vitro and in vivo. However, the stability of IPA1 protein is not affected by IPI7-mediated ubiquitination. The IPI7-promoted K29-polyubiquitination of IPA1 is induced by Magnaporthe oryzae infection and required for phosphorylated IPA1 to transactivate WRKY45 expression for immune response but not for plain IPA1 to transactivate DENSE AND ERECT PANICLES 1 ( DEP1 ) expression for panicle development. IPI7 knockout impairs IPA1-mediated immunity but not yield. Our study reveals that plants utilize non-proteolytic K29-ubiquitination as a response to pathogen infection to fine-tune IPA1 transactivation activity for promoting immunity. In this paper, the E3 ubiquitin ligase IPI7 is found to fine-tune the transactivation activity of IPA1 through non-hydrolyzed K29-ubiquitination chain, thereby timely regulating rice disease resistance during Magnaporthe oryzae infection.

Hydrogen peroxide (H 2 O 2 ) is a ubiquitous signal regulating many biological processes, including innate immunity, in all eukaryotes. However, it remains largely unknown that how transcription factors directly sense H 2 O 2 in eukaryotes. Here, we report that rice basic/helix-loop-helix transcription factor bHLH25 directly senses H 2 O 2 to confer resistance to multiple diseases caused by fungi or bacteria. Upon pathogen attack, rice plants increase the production of H 2 O 2 , which directly oxidizes bHLH25 at methionine 256 in the nucleus. Oxidized bHLH25 represses miR397b expression to activate lignin biosynthesis for plant cell wall reinforcement, preventing pathogens from penetrating plant cells. Lignin biosynthesis consumes H 2 O 2 causing accumulation of non-oxidized bHLH25. Non-oxidized bHLH25 switches to promote the expression of Copalyl Diphosphate Synthase 2 ( CPS2 ), which increases phytoalexin biosynthesis to inhibit expansion of pathogens that escape into plants. This oxidization/non-oxidation status change of bHLH25 allows plants to maintain H 2 O 2 , lignin and phytoalexin at optimized levels to effectively fight against pathogens and prevents these three molecules from over-accumulation that harms plants. Thus, our discovery reveals a novel mechanism by which a single protein promotes two independent defense pathways against pathogens. Importantly, the bHLH25 orthologues from available plant genomes all contain a conserved M256-like methionine suggesting the broad existence of this mechanism in the plant kingdom. Moreover, this Met-oxidation mechanism may also be employed by other eukaryotic transcription factors to sense H 2 O 2 to change functions.