Estimates on nitrogen uptake in the subsequent wheat by aboveground and root residue and rhizodeposition of using peanut labeled with^(15)N isotope on the North China Plain

Leguminous crops play a vital role in enhancing crop yield and improving soil fertility. Therefore, it can be used as an organic N source for improving soil fertility. The purpose of this study was to(i) quantify the amounts of N derived from rhizodeposition, root and above-ground biomass of peanut residue in comparison with wheat and(ii) estimate the effect of the residual N on the wheat-growing season in the subsequent year. The plants of peanut and wheat were stem fed with 15 N urea using the cotton-wick method at the Wuqiao Station of China Agricultural University in 2014. The experiment consisted of four residue-returning strategies in a randomized complete-block design:(i) no return of crop residue(CR0);(ii) return of above-ground biomass of peanut crop(CR1);(iii) return of peanut root biomass(CR2); and(iv) return of all residue of the whole peanut plant(CR3). The 31.5 and 21% of the labeled 15 N isotope were accumulated in the above-ground tissues(leaves and stems) of peanuts and wheat, respectively. N rhizodeposition of peanuts and wheat accounted for 14.91 and 3.61% of the BG15 N, respectively. The 15 N from the below-ground 15 N-labeled of peanuts were supplied 11.3, 5.9, 13.5, and 6.1% of in the CR0, CR1, CR2, and CR3 treatments, respectively. Peanut straw contributes a significant proportion of N to the soil through the decomposition of plant residues and N rhizodeposition. With the current production level on the NCP, it is estimated that peanut straw can potentially replace 104 500 tons of synthetic N fertilizer per year. The inclusion of peanut in rotation with cereal can significantly reduce the use of N fertilizer and enhance the system sustainability.

Electrosynthesis of ^(15)N-labeled amino acids from ^(15)N-nitrite and ketonic acids

^(15)N isotope-labeled amino acids(^(15)N-amino acids)are crucial in the fields of biology,medicine,and chemistry.^(15)N-amino acids are conventionally synthesized through microbial fermentation and chemical reductive amination of ketonic acids methodologies,which usually require complicated procedures,high temperatures,or toxic cyanide usage,causing energy and environmental concerns.Here,we report a sustainable pathway to synthesize ^(15)N-amino acids from readily available ^(15)N-nitrite(^(15)NO_(2)-)and biomass-derived ketonic acids under ambient conditions driven by renewable electricity.A mechanistic study demonstrates a ^(15)N-nitrite→^(15)NH_(2)OH→^(15)N-pyruvate oxime→^(15)N-alanine reaction pathway for ^(15)N-alanine synthesis.Moreover,this electrochemical strategy can synthesize six ^(15)N-amino acids with 68%–95%yields.Furthermore,a ^(15)N-labeled drug of ^(15)N-tiopronin,the most commonly used hepatitis treatment drug,is fabricated using ^(15)N-glycine as the building block.Impressively,^(15)N sources can be recycled by the electrooxidation of ^(15)NH4^(+) to ^(15)NO_(2)-with a method economy.This work opens an avenue for the green synthesis of ^(15)N-labeled compounds or drugs.

Quantitative and Functional Phosphoproteomic Analysis Reveals that Ethylene Regulates Water Transport via the C-Terminal Phosphorylation of Aquaporin PIP2;1 in Arabidopsis

Ethylene participates in the regulation of numerous cellular events and biological processes, including wa- ter loss, during leaf and flower petal wilting. The diverse ethylene responses may be regulated via dynamic interplays between protein phosphorylation/dephosphorylation and ubiquitin/26S proteasome-mediated protein degradation and protease cleavage. To address how ethylene alters protein phosphorylation through multi-furcated signaling pathways, we performed a lSN stable isotope labelling-based, differential, and quantitative phosphoproteomics study on air- and ethylene-treated ethylene-insensitive Arabidopsis double loss-of-function mutant ein3-1/eill-1. Among 535 non-redundant phosphopeptides identified, two and four phosphopeptides were up- and downregulated by ethylene, respectively. Ethylene- regulated phosphorylation of aquaporin PIP2;1 is positively correlated with the water flux rate and water loss in leaf. Genetic studies in combination with quantitative proteomics, immunoblot analysis, protoplast swelling/shrinking experiments, and leaf water loss assays on the transgenic plants expressing both the wild-type and S280A/S283A-mutated PIP2;1 in the both Col-O and ein3eill genetic backgrounds suggest that ethylene increases water transport rate in Arabidopsis cells by enhancing S280/S283 phosphorylation at the C terminus of PIP2;1. Unknown kinase and/or phosphatase activities may participate in the initial up- regulation independent of the cellular functions of EIN3/EIL1. This finding contributes to our understanding of ethylene-regulated leaf wilting that is commonly observed during post-harvest storage of plant organs.

Radicle pruning by seed-eating animals helps oak seedlings absorb more soil nutrient

Although radicle pruning has well been observed in plant-animal interactions,research has not been conducted to determine how radicle pruning by seed-eating animals regulates nutrition mobilization of cotyledonary reserves and absorption of soil nutrients.We used stable nitrogen isotopes to test how acorns of early-germinating oak species(Quercus variabilis,Q.aliena,and Q.mogolica)trade off nutrients in the cotyledons and those in the soil in response to radicle pruning by seed-eating rodents.Radicle pruning by rodents resulted in root branching in the 3 early-germinating oak species.Moreover,radicle pruning increased shoot dry weight and substantially reduced the root-to-shoot ratio of oak species.Corresponding to the decreased dry weight of roots and root-to-shoot ratio,the dry weight of the remnant cotyledons was higher after radicle pruning in the 3 oak species.We provided first evidence that radicle pruning by seed-eating animals improved seedling performance of early-germinating oaks by increasing absorption of nutrients from soil.The results indicate that early-germinating oak seedlings trade off nutrition budget by altering nutrient absorption from soil and reserve mobilization from cotyledons in response to radicle pruning by seed-eating animals.Our study provided new insight into the nutrition allocation mechanism of young seedlings in response to radicle pruning by seed-eating animals,reflecting a mutualistic interaction between early-germinating oak and food-hoarding animals.