Regulation of maize root growth by local phosphorus availability, sucrose metabolism, and partitioning.

BACKGROUND AND AIMS: Understanding how maize roots proliferate in phosphorus (P)-rich soil patches is critical for improving nutrient acquisition and crop productivity. This study explores the mechanisms of root adaptation to heterogeneous P availability, focusing on sucrose metabolism and the role of local P signals. METHODS: A split-root system with chambers of differing Pi concentrations (0 and 500 µM) was used to examine maize root responses. Various physiological and biochemical parameters, including root growth, sucrose partitioning, enzyme activities, and gene expression, were measured to elucidate the underlying mechanisms. KEY RESULTS: Root proliferation, particularly of second-order lateral roots, was markedly enhanced in P-rich patches. Sucrose was preferentially allocated to the Pi-supplied side, as confirmed by Fourier-transform infrared (FTIR) microscopy. Sucrose content in these roots decreased, indicating active metabolism. Higher activities of cell-wall invertase and sucrose synthase were observed in the Pi-supplied roots, supporting enhanced carbohydrate utilization. CONCLUSIONS: Local P availability triggers significant adjustments in sucrose metabolism and allocation, enhancing the sink capacity of maize roots in P-rich patches. These changes facilitate efficient lateral root proliferation and Pi utilization, highlighting the critical role of local P signals in nutrient acquisition strategies. This research provides deeper insights into the adaptive responses of maize to heterogeneous P environments, offering potential strategies for improving crop nutrient efficiency.

Comparison of endovascular interventional embolization and microsurgical clipping for ruptured cerebral aneurysms: impact on patient outcomes.

OBJECTIVE: To compare the therapeutic efficacy of endovascular interventional embolization and microsurgical clipping in patients with ruptured cerebral aneurysms and investigate their subsequent influence on inflammatory indices, neurological function, prognosis, and recovery. METHODS: The two groups were compared in terms of surgery duration, hospital stay, Hunt-Hess classification, and inflammatory indices before and after the surgery, as well as National Institutes of Health Stroke Scale (NIHSS), Baethel Index (BI), and one-year prognosis of patients affected. RESULTS: The surgery duration and hospital stay of the intervention group were (116.27 ± 12.32) min and (19.82 ± 2.26) d, respectively, and those of the clipping group was (173.87 ± 10.39) min and (24.11 ± 2.33) d, respectively (both p < 0.05). Neither the intervention nor the microscopic approach had a significant impact on the severity of the patients' conditions in terms of Hunt-Hess classification (p > 0.05). In the intervention group, CRP was changed to (5.31 ± 1.22) mg/L and PCT decreased to (1.17 ± 0.39) µg/L after the surgery, while the corresponding values in clipping group were (9.78 ± 2.35) mg/L and (2.75 ± 0.81) µg/L (p > 0.05). After surgery, both groups' NIHSS scores declined dramatically, with the intervention group scoring lower than the microscopy group (6.81 ± 1.22 vs 8.72 ± 1.27) (p < 0.05). CONCLUSION: The findings of this study support the potential advantages of endovascular interventional embolization (coiling) over microsurgical clipping for the management of ruptured cerebral aneurysms. These advantages include shorter surgical duration, reduced hospital stay, lower inflammatory response, improved neurological and functional outcomes, and better long-term prognosis.

Differences in foliar phosphorus fractions, rather than in cell-specific phosphorus allocation, underlie contrasting photosynthetic phosphorus use efficiency among chickpea genotypes.

Although significant intraspecific variation in photosynthetic phosphorus (P) use efficiency (PPUE) has been shown in numerous species, we still know little about the biochemical basis for differences in PPUE among genotypes within a species. Here, we grew two high PPUE and two low PPUE chickpea (Cicer arietinum) genotypes with low P supply in a glasshouse to compare their photosynthesis-related traits, total foliar P concentration ([P]) and chemical P fractions (i.e. inorganic P (Pi), metabolite P, lipid P, nucleic acid P, and residual P). Foliar cell-specific nutrient concentrations including P were characterized using elemental X-ray microanalysis. Genotypes with high PPUE showed lower total foliar [P] without slower photosynthetic rates. No consistent differences in cellular [P] between the epidermis and mesophyll cells occurred across the four genotypes. In contrast, high PPUE was associated with lower allocation to Pi and metabolite P, with PPUE being negatively correlated with the percentage of these two fractions. Furthermore, a lower allocation to Pi and metabolite P was correlated with a greater allocation to nucleic acid P, but not to lipid P. Collectively, our results suggest that a different allocation to foliar P fractions, rather than preferential P allocation to specific leaf tissues, underlies the contrasting PPUE among chickpea genotypes.

RBM12 regulates the progression of hepatocellular cancer via miR-497-5p/CPNE1 Axis.

BACKGROUND: Hepatocellular Carcinoma (HCC), also called hepatocellular cancer, has emerged as a highly prevalent malignancy globally. By binding to specific RNA via one or more spherical RNA Domains (RBDs) or RNA Motifs (RBMs), RNA Binding Proteins (RBPs) can affect RNA modification, splicing, localization, translation, and stability. METHODS: This paper builds on previous research by further investigating the impact of RBM12 on LC progression. In order to determine the effect of RBM12 expression on the prognosis of patients with hepatocellular cancer, we first investigated its expression in liver cancer cells (LCC) and tissues. The effect of RBM12 on the malignant biological behavior of LCC was subsequently detected using cytological experiments. To explore the upstream mechanism affecting RBM12, we predicted the miRNA targeting RBM12. According to the database, miR-497-5p was the best candidate gene. The double Luciferase reporter gene experiment was executed to validate the bounding of miR-497-5p with RBM12. RESULTS: According to the cytological experiments, a high RBM12 expression promoted the propagation, migration, and invasion of LCC and impeded liver cancer cell apoptosis. By secreting TGF-ß1, RBM12 could induce the EMT process. The miR-497-5p expression is suppressed in hepatocellular cancer. As shown by the CCK8, plate cloning, Transwell, EDU, and other experiments, miR-497-5p suppressed RBM12 expression and tumor growth. The double Luciferase reporter gene system was utilized to verify the combination of miR-497-5p and RBM12. The CPNE1 is a downstream gene regulated by RBM12. A high CPNE1 expression was exhibited in LCC and tissues. The CPNE1 is essential in the process where RBM12 promotes the incidence and progression of liver cancer. CONCLUSIONS: By elucidating the exact molecular mechanism through which RBM12 promotes the initiation and progression of LC, thus, the current investigation provides some reference for the clinical management of LC.

Linking root exudation to belowground economic traits for resource acquisition.

The concept of a root economics space (RES) is increasingly adopted to explore root trait variation and belowground resource-acquisition strategies. Much progress has been made on interactions of root morphology and mycorrhizal symbioses. However, root exudation, with a significant carbon (C) cost (c. 5-21% of total photosynthetically fixed C) to enhance resource acquisition, remains a missing link in this RES. Here, we argue that incorporating root exudation into the structure of RES is key to a holistic understanding of soil nutrient acquisition. We highlight the different functional roles of root exudates in soil phosphorus (P) and nitrogen (N) acquisition. Thereafter, we synthesize emerging evidence that illustrates how root exudation interacts with root morphology and mycorrhizal symbioses at the level of species and individual plant and argue contrasting patterns in species evolved in P-impoverished vs N-limited environments. Finally, we propose a new conceptual framework, integrating three groups of root functional traits to better capture the complexity of belowground resource-acquisition strategies. Such a deeper understanding of the integrated and dynamic interactions of root morphology, root exudation, and mycorrhizal symbioses will provide valuable insights into the mechanisms underlying species coexistence and how to explore belowground interactions for sustainable managed systems.

Flavonoids are involved in phosphorus-deficiency-induced cluster-root formation in white lupin.

BACKGROUND AND AIMS: Initiation of cluster roots in white lupin (Lupinus albus) under phosphorus (P) deficiency requires auxin signalling, whereas flavonoids inhibit auxin transport. However, little information is available about the interactions between P deficiency and flavonoids in terms of cluster-root formation in white lupin. METHODS: Hydroponic and aeroponic systems were used to investigate the role of flavonoids in cluster-root formation, with or without 75 µm P supply. KEY RESULTS: Phosphorus-deficiency-induced flavonoid accumulation in cluster roots depended on developmental stage, based on in situ determination of fluorescence of flavonoids and flavonoid concentration. LaCHS8, which codes for a chalcone synthase isoform, was highly expressed in cluster roots, and silencing LaCHS8 reduced flavonoid production and rootlet density. Exogenous flavonoids suppressed cluster-root formation. Tissue-specific distribution of flavonoids in roots was altered by P deficiency, suggesting that P deficiency induced flavonoid accumulation, thus fine-tuning the effect of flavonoids on cluster-root formation. Furthermore, naringenin inhibited expression of an auxin-responsive DR5:GUS marker, suggesting an interaction of flavonoids and auxin in regulating cluster-root formation. CONCLUSIONS: Phosphorus deficiency triggered cluster-root formation through the regulation of flavonoid distribution, which fine-tuned an auxin response in the early stages of cluster-root development. These findings provide valuable insights into the mechanisms of cluster-root formation under P deficiency.

Closing yield gaps in China by empowering smallholder farmers.

Sustainably feeding the world's growing population is a challenge, and closing yield gaps (that is, differences between farmers' yields and what are attainable for a given region) is a vital strategy to address this challenge. The magnitude of yield gaps is particularly large in developing countries where smallholder farming dominates the agricultural landscape. Many factors and constraints interact to limit yields, and progress in problem-solving to bring about changes at the ground level is rare. Here we present an innovative approach for enabling smallholders to achieve yield and economic gains sustainably via the Science and Technology Backyard (STB) platform. STB involves agricultural scientists living in villages among farmers, advancing participatory innovation and technology transfer, and garnering public and private support. We identified multifaceted yield-limiting factors involving agronomic, infrastructural, and socioeconomic conditions. When these limitations and farmers' concerns were addressed, the farmers adopted recommended management practices, thereby improving production outcomes. In one region in China, the five-year average yield increased from 67.9% of the attainable level to 97.0% among 71 leading farmers, and from 62.8% to 79.6% countywide (93,074 households); this was accompanied by resource and economic benefits.

Heterogeneous nutrient supply promotes maize growth and phosphorus acquisition: additive and compensatory effects of lateral roots and root hairs.

BACKGROUND AND AIMS: Root proliferation is a response to a heterogeneous nutrient distribution. However, the growth of root hairs in response to heterogeneous nutrients and the relationship between root hairs and lateral roots remain unclear. This study aims to understand the effects of heterogeneous nutrients on root hair growth and the trade-off between root hairs and lateral roots in phosphorus (P) acquisition. METHODS: Near-isogenic maize lines, the B73 wild type (WT) and the rth3 root hairless mutant, were grown in rhizoboxes with uniform or localized supply of 40 (low) or 140 (high) mg P kg-1 soil. RESULTS: Both WT and rth3 had nearly two-fold greater shoot biomass and P content under local than uniform treatment at low P. Significant root proliferation was observed in both WT and rth3 in the nutrient patch, with the WT accompanied by an obvious increase (from 0.7 to 1.2 mm) in root hair length. The root response ratio of rth3 was greater than that of WT at low P, but could not completely compensate for the loss of root hairs. This suggests that plants enhanced P acquisition through complementarity between lateral roots and root hairs, and thus regulated nutrient foraging and shoot growth. The disappearance of WT and rth3 root response differences at high P indicated that the P application reduced the dependence of the plants on specific root traits to obtain nutrients. CONCLUSIONS: In addition to root proliferation, the root response to a nutrient-rich patch was also accompanied by root hair elongation. The genotypes without root hairs increased their investment in lateral roots in a nutrient-rich patch to compensate for the absence of root hairs, suggesting that plants enhanced nutrient acquisition by regulating the trade-off of complementary root traits.

Wheat growth responses to soil mechanical impedance are dependent on phosphorus supply.

Increased mechanical impedance induced by soil drying or compaction causes reduction in plant growth and crop yield. However, how mechanical impedance interacts with nutrient stress has been largely unknown. Here, we investigated the effect of mechanical impedance on the growth of wheat seedlings under contrasting phosphorus (P) supply in a sand culture system which allows the mechanical impedance to be independent of water and nutrient availability. Two wheat genotypes containing the Rht-B1a (tall) or Rht-B1c (gibberellin-insensitive dwarf) alleles in the Cadenza background were used and their shoot and root traits were determined. Mechanical impedance caused a significant reduction in plant growth under sufficient P supply, including reduced shoot and root biomass, leaf area and total root length. By contrast, under low P supply, mechanical impedance did not affect biomass, tiller number, leaf length, and nodal root number in both wheat genotypes, indicating that the magnitude of the growth restriction imposed by mechanical impedance was dependent on P supply. The interaction effect between mechanical impedance and P level was significant on most plant traits except for axial and lateral root length, suggesting an evident physical and nutritional interaction. Our findings provide valuable insights into the integrated effects of plants in response to both soil physical and nutritional stresses. Understanding the response patterns is critical for optimizing soil tillage and nutrient management in the field.

Neighbouring plants modify maize root foraging for phosphorus: coupling nutrients and neighbours for improved nutrient-use efficiency.

Nutrient distribution and neighbours can impact plant growth, but how neighbours shape root-foraging strategy for nutrients is unclear. Here, we explore new patterns of plant foraging for nutrients as affected by neighbours to improve nutrient acquisition. Maize (Zea mays) was grown alone (maize), or with maize (maize/maize) or faba bean (Vicia faba) (maize/faba bean) as a neighbour on one side and with or without a phosphorus (P)-rich zone on the other in a rhizo-box experiment. Maize demonstrated root avoidance in maize/maize, with reduced root growth in 'shared' soil, and increased growth away from its neighbours. Conversely, maize proliferated roots in the proximity of neighbouring faba bean roots that had greater P availability in the rhizosphere (as a result of citrate and acid phosphatase exudation) compared with maize roots. Maize proliferated more roots, but spent less time to reach, and grow out of, the P patches away from neighbours in the maize/maize than in the maize/faba bean experiment. Maize shoot biomass and P uptake were greater in the heterogeneous P treatment with maize/faba bean than with maize/maize system. The foraging strategy of maize roots is an integrated function of heterogeneous distribution of nutrients and neighbouring plants, thus improving nutrient acquisition and maize growth. Understanding the foraging patterns is critical for optimizing nutrient management in crops.