Cotton seeds, as the main by-product of cotton, are not only an important raw material for edible oil and feed but also a source of biofuel. The quality of cotton seeds directly affects cotton planting and is closely related to the yield and fiber quality. However, the molecular mechanism governing cotton seed size remains largely unexplored. This study investigates the regulatory mechanisms of cotton seed size by focusing on two cotton genotypes, N10 and N12, which exhibit notable phenotypic variations across multiple environments. Developing seeds were sampled at various stages (5, 20, 30, and 35 DPA) and subjected to RNA-seq. Temporal pattern clustering and WGCNA on differentially expressed genes identified 413 candidate genes, including these related to sugar metabolism that were significantly enriched in transcriptional regulation. A genetic transformation experiment indicated that the overexpression of the GhUXS5 gene encoding UDP-glucuronate decarboxylase 5 significantly increased seed size, suggesting an important role of GhUXS5 in regulating cotton seed size. This discovery provides crucial insights into the molecular mechanisms controlling cotton seed size, helping to unravel the complex regulatory network and offering new strategies and targets for cotton breeding to enhance the economic value of cotton seeds and overall cotton yield.

Vacuolar Pi transporters (VPTs) have recently been identified as important regulators of cellular Pi status in Arabidopsis thaliana and Oryza sativa. In the oil crop Brassica napus, BnA09PHT5;1a and BnC09PHT5;1a are two homologs of AtPHT5;1, the vacuolar Pi influx transporter in Arabidopsis. Here, we show that Pi deficiency induces the transcription of both homologs of PHT5;1a genes in B. napus leaves. Brassica PHT5;1a double mutants (DM) had smaller shoots and higher cellular Pi concentrations than wild-type (WT, Westar 10), suggesting the potential role of BnPHT5;1a in modulating cellular Pi status in B. napus. A proteomic analysis was performed to estimate the role of BnPHT5;1a in Pi fluctuation. Results show that Pi deprivation disturbs the abundance of proteins in the physiological processes involved in carbohydrate metabolism, response to stimulus and stress in B. napus, while disruption of BnPHT5;1a genes may exacerbate these processes. Besides, the processes of cell redox homeostasis, lipid metabolic and proton transmembrane transport are supposed to be unbalanced in BnPHT5;1a DM under the -Pi condition. Noteworthy, disruption of BnPHT5;1a genes severely alters the abundance of proteins related to ATP biosynthesis, and proton/inorganic cation transmembrane under normal Pi condition, which might contribute to B. napus growth limitations. Additionally, seven new protein markers of Pi homeostasis are identified in B. napus. Taken together, this study characterizes the important regulatory role of BnPHT5;1a genes as vacuolar Pi influx transporters in Pi homeostasis in B. napus.

为明确被子植物的离子组及其与植物种类的关系,以及不同科被子植物叶片离子组组成的差异与联系,本研究对《狮山兰芷》中收录的华中农业大学校园种植的被子植物进行系统分类,从中筛选出102种被子植物,测定叶片中氮(N)、磷(P)、钾(K)、钙(Ca)、镁(Mg)、硫(S)、铁(Fe)、锰(Mn)、铜(Cu)、锌(Zn)、硼(B)、钼(Mo)和镍(Ni)等13种矿质元素的浓度,建立这些植物离子组指纹图谱并分析这些植物的离子组成分及其与植物种类的关系.结果显示,叶片中N、K和Ca 3种元素含量最高,P、Mg和S其次,微量元素含量最低.其中,豆目植物叶片N含量较高,石竹目植物叶片中P和K含量较高,7种微量元素含量在这102种被子植物叶片中也表现出较显著的差异.相关性分析显示,每种元素都至少与其他4种矿质营养元素存在显著相关性,其中Ca分别与Mg和B,N、P和K三者之间都存在极显著的正相关,Zn与Ca、Mg,P和Mn之间存在极显著的负相关.主成分分析显示,同一科植物的叶片离子组相似,不同科植物叶片离子组不同.聚类分析结果显示,Ca、N、K、S、Mg、P这6种矿质元素在不同科植物离子组的变异中具有较大的贡献率.以上结果表明,被子植物的系统发育与叶片离子组相互关联,同一科的植物叶片离子组表现出高度的相似性,我们或许能通过植物叶片离子组对植物进行种类鉴定.

The coordinated development of the Water-Land-Food (WLF) nexus is important for realizing sustainable food production and ensuring national food security. Based on the symbiosis system theory, this study used the Entropy weight TOPSIS method to calculate the WLF nexus of 30 provinces, municipalities and autonomous regions in China from 2003 to 2019. Taking the problem of decentralized food crop cultivation in China as the breakthrough point and using the Panel Tobit Model to empirically explore the threat of decentralized food crop cultivation to the WLF nexus. The results indicated that: (i) The average level of decentralized food crop cultivation index in China for the period 2003–2019 is 2.599 and the growth rate is −12.64%, while the WLF nexus index is 0.317, and the growth rate is 2.42%. Decentralized food crop cultivation showed a fluctuating downward trend in all regions of China, especially in the southwest and northwest regions. However, the WLF nexus index level belonging to the northeastern and Huang-Huai-Hai regions of China is higher, which presents a trend of first decreasing and then increasing. (ii) While the extent of decentralized food crop cultivation threatens the coordination of the WLF nexus in China, it has a time lag. (iii) The decentralized food crop cultivation in non-food producing areas (NFPA) rather than major food producing areas (MFPA) will threaten the WLF nexus. (iv) Compared with the higher WLF nexus index region, the negative effect of decentralized food crop cultivation is more obvious in the lower index region. (v) WFL nexus in the adjacent provinces of China showed regional clustering. Decentralized food crop cultivation will threaten the WLF nexus both in the inner province and adjacent regions. This study argues that the government can use financial subsidies to correct the problem of decentralized food crop cultivation, optimize the level of agricultural outsourcing services, and improve the market for water and land rights, thereby enhancing the WLF system coordination in China.

Oilseed rape (Brassica napus L.) is the most important temperate oil crop globally. Maintenance of soil phosphate (Pi) availability, through the application of Pi fertilizers and manures, is needed to maintain seed yield of oilseed rape. Over-application of the Pi fertilizers results in Pi accumulation in agricultural soils and adjacent ecosys-tems, where it can drive eutrophication in freshwater and coastal systems. In this study, two years of field ex-periments were conducted to explore the optimal Pi fertilizer application rate for four oilseed rape cultivars and the potential of nature-based solutions including Pi solubilizing bacteria (PSB) and rooting agent (RA) to reduce Pi fertilizer application rates for oilseed rape. The seed yields of cultivars Shengguang 168 (SG168) and Huayouza 9 (HYZ9) were significantly higher than those of cultivars Zhongyouza 19 (ZYZ19) and Zhongshuang 11 (ZS11) across all Pi application rates. In comparison with Farmers' fertilizer practice (P26.2, 26.2 kg P ha-1), Pi fertilizers could be reduced by more than 25% for the four cultivars, and be reduced by as much as 50% for SG168. The shoot dry weight and seed yield of ZS11 with the addition of RA at P21.0 (21.0 kg P ha-1) in Expt. 2-1 and P15.7 (15.7 kg P ha-1) in Expt. 2-2 showed no significant difference to that of P26.2 at the ripening stage, but were significantly higher than that of P21.0 and that of P15.7, respectively. At P0 (0 kg P ha-1), addition of PSB significantly increased the shoot dry weight and seed yield of ZS11 at the ripening stage. However, at P21.0 in Expt. 2-1 or at P15.7 in Expt. 2-2, addition of PSB had no effect on shoot dry weight and seed yield of ZS11. These results highlighted the feasibility and potential to reduce the application rate and improve the use efficiency of Pi fertilizers in oilseed rape using nature-based solutions.

Optimal phosphorus (P) managements can improve the crop yield without reducing soil P supply capacity over the long term. In this study, the rapeseed–rice rotation experiments were conducted to evaluate the effect of five optimal P fertilizer managements, including the addition of RA (rooting agents), PSB (phosphate solubilizing bacteria), CMP (calcium and magnesium phosphate fertilizer), DP1 (starter P) and DP2 (foliar fertilizer) with the reduction of 40% (in the 1st rapeseed season) and 75% (in the 2nd rapeseed season) P fertilizers of farmers’ fertilizer practice (FFP) on crop productivity and soil P fertility in low and high P fertility soils. Seed yield, P partial factor productivity, and P recovery efficiency of both cultivars, Shengguang168 (SG168) and Zhongshuang 11 (ZS11), were significantly improved under optimal P managements, and the increase of them in low P fertility soil was more than that in high P fertility soil. Total P surplus was lower under optimal P managements than under FFP in both P fertility soils. The increasing amount of crop yields under optimal P managements for both cultivars was equivalent to that of 16.0–38.3 kg P2O5 hm−2 of P fertilizer application, and the order of the optimal P managements was as follows: RA > PSB > CMP > DP1 > DP2. In addition, the grain yield of rotated rice cultivar Longliangyou1212 (LLY1212) without P supply was not reduced in both fertility soils. Compared with low P fertility soil, yields of SG168, ZS11 and LLY1212 in high P fertility soil increased by 28.1%–71.7%, 28.3%–78.9% and 26.2%–47.2% at the same treatment, respectively. In summary, optimal P managements in the rapeseed season could stabilize the crop yield, promote P use efficiency and the capacity of soil P supply in the rapeseed–rice rotation, especially in low P fertility soil.