Significance Phosphate (Pi) is a primary nutrient for plant growth. Because of the low availability of soil Pi, the Pi starvation signaling in plants is gaining great interest. Arabidopsis AtPHR1 and its rice homologue OsPHR2 are known to be central transcription factors in Pi homeostasis; however, the mechanism of how plants sense external Pi fluctuation to regulate the activity of AtPHR1/OsPHR2 has been elusive. Here, we identify rice SPX1 and SPX2 as Pi-dependent inhibitors of PHR2, implicating SPX1 and SPX2 in the Pi-sensing mechanism. We also show that the SPX domain of SPX1 and SPX2 is critical for repressing PHR2 binding to cis elements by protein interaction. The discovery of cellular nutrient concentration-dependent fine-tuning sheds light on a novel mechanism of plant adaption to environmental cues.
The Qinghai-Tibetan Plateau is experiencing significant nitrogen (N) deposition and increased precipitation. Although changes in N deposition and precipitation may cause changes in the composition and diversity of plants, the relationships between plant diversity and soil microbial diversity still has not been fully researched. Thus, we conducted a field simulation experiment in an alpine meadow that included three N and two water (W) addition levels, as well as their interactions. The abbreviations of all treatments are shown below: CK, control; W, added water; N5, added 5 g N m−2 yr−1; N10, added 10 g N m−2 yr−1; N5W, added N5 and W; N10W, added N10 and W. The dominant plant species belong to the Gramineae family and include Elymus dahuricus, Stipa capillata, Poa pratensis and Agropyron cristatum. One year later after N and water addition, the results indicated that soil pH decreased with N addition, and with a combination of N and W addition together. High rate of N addition significantly lowered plant diversity. For different plant functional groups, the relative abundance of grasses significantly increased, while the relative abundance of forbs significantly decreased under N10, N5W and N10W treatments. Under N10W treatment, the relative abundance of legumes was significantly reduced, while the relative abundance of cyperaceae was significantly increased. W and N interactions significantly decreased soil bacterial and fungal diversity. N addition showed an indirect effect on the fungal diversity by directly affecting plant productivity. Water addition showed an indirect effect on bacterial diversity by directly affecting plant diversity. Soil bacterial diversity showed a positive correlation with plant diversity, while soil fungal diversity had no significant correlation with plant diversity, but had a negative correlation with plant productivity. It also indicates that the strength of feedbacks between aboveground and belowground biodiversity will vary depending on which groups of soil biota are considered.
This work aimed to investigate how two different types of forage (saline and alkaline) impact the meat quality and muscle metabolism of Tibetan sheep. An integrative multi-omics analysis of meat quality and different metabolites was performed using untargeted and targeted metabolomics approaches. The research results indicated that GG grass (saline and alkaline forage) possessed superior characteristics in terms of apparent quality and secondary metabolite content compared with HG grass (Non saline alkali forage), regardless of the targeted metabolites or non-targeted ones. Simultaneously, under stress conditions, the carbohydrates-rich salt-alkali grass play a significant role in slowing down the decline in pH, increasing the unsaturated fatty acid content and reducing the thawing loss in Tibetan sheep. This study provides an understanding of the impact of different salt-alkali grass on the quality of Tibetan sheep meat, while providing a scientific basis for the future development of salt-alkali livestock industry.
Field crops influence the biotic properties of the soil, impacting the health and productivity of subsequent crops. Polymerase chain reaction and 454 GS FLX pyrosequencing of amplicons were used to clarify the legacy of chickpea and pea crops on the quality of the bacterial community colonizing the root endosphere of subsequent crops of wheat, in a replicated field study. Similar communities of root endosphere bacteria were formed in durum wheat grown after pea and chickpea crops when chickpea crops were terminated as early as pea (July). Termination of the chickpea crops in September led to the domination of Firmicutes in wheat root endosphere; Actinobacteria dominated the wheat root endosphere following early pulse crop termination. The architecture of wheat plants was correlated with the composition of its root endosphere community. High grain yield was associated with the production of fewer but larger wheat heads, the abundance of endospheric Actinobacteria and Acidobacteria, and the scarcity of endospheric Firmicutes. Pulse termination time affected wheat root endosphere colonization strongly in 2009 but weakly in 2010, an abnormally wet year. This study improved our understanding of the so-called “crop rotation effect” in pulse–wheat systems and showed how this system can be manipulated through agronomic decisions.
Background.Soil aggregate-size classes and microbial communities within the aggregates are important factors regulating the soil organic carbon (SOC) turnover.However, the response of soil bacterial and fungal communities in aggregates to litter decomposition in different aggregate-size classes is poorly understand.Methods.Soil samples from un-grazed natural grassland were separated into four dry aggregate classes of different sizes (2-4 mm, 1-2 mm, 0.25-1 mm and <0.25 mm).Two types of plant litter (leaf and stem) of Leymus chinensis were added to each of the four aggregate class samples.The CO2 release rate, SOC storage and soil microbial communities were measured at the end of the 56-day incubation.Results.The results showed that the 1-2 mm aggregate had the highest bacterial Shannon and CO2 release in CK and leaf addition treatments, and the SOC in the < 0.25 mm aggregate was higher than that in the others across the treatments.The relative abundance of Ascomycota was higher in the 2-4 mm and < 0.25 mm aggregates than in the 1-2 mm and 0.25-1 mm aggregates in the treatment without litter addition, and the relative abundance of Aphelidiomycota was lower in the 2-4 mm and < 0.25 mm aggregates than in the 1-2 mm and 0.25-1 mm aggregates.Also, litter addition increased the relative abundance of Proteobacteria and Bacteroidetes, but decreased the relative abundance of Acidobacteria, Gemmatimonadetes, and Actinobacteria.The relative abundance of Ascomycota and Aphelidiomycota increased by more than 10% following leaf litter addition.The bacterial Shannon index had a significantly positive and direct effect on SOC concentration and CO2 release, while the fungal Shannon index was significantly correlated with SOC concentration.Our results indicate that the soil bacterial diversity contributes positively to both carbon emissions and carbon storage, whereas soil fungal diversity can promote carbon storage and decrease carbon emissions.
This study was carried out to make the most of them as the fundamental data for reasonable weed control when population of weeds was observed in the alternated fields of lowland and upland. The annual and the perennial paddy weeds in the continuous paddy rice field remarkably decreased when compared to that in the alternated field of paddy rice and soybean. The longer was the duration of upland field condition, the less was the population of lowland weeds and the more was the population of upland weeds. Biennial weeds in the contiuous paddy rice field were less than that in the rotated field of paddy rice and soybean, and this tendency was clear in Alopecurus aequalis Sobol. In the continuous cropping of paddy rice, population of biennial weeds in the culverted field was higher than that in the unculverted one, but in the continuous cropping of soybean this tendency was vice versa.
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