查看更多>>摘要：Nitrogen (N) deficiency limits the production of apple (Malus domestica) on the Loess Plateau, which is the largest apple-producing region in China. Autophagy is a conserved degradation and recycling pathway in eukaryotes that has been reported to play a key role in the responses of plants to N deficiency. We previously identified the core autophagy-related gene MdATG5a from apple and showed that overexpression of this gene improves the drought tolerance of apple plants. Here, we showed that MdATG5a overexpression enhances root growth and the root N uptake of apple plants under low-N conditions and contributes to improving N use efficiency. MdATG5a positively regulated root N uptake by activating the shikimate pathway to increase levels of phenylalanine and tryptophan, which promoted the accumulation of flavonoids and IAA in apple roots under low-N conditions. In addition, MdATG5a was demonstrated to affect the expression of genes involved in root development in response to N deficiency. Moreover, we also found that autophagy activity was higher in the roots of MdATG5a-over-expressing apple plants compared with wild-type plants under low-N conditions. Overall, the results of our study provide new insights into the association between MdATG5a-mediated autophagy and the root N uptake of apple plants under low-N conditions.
Ding, ZheliZhao, FengliangZhu, ZhiqiangAli, Esmat F. F....
8页
查看更多>>摘要：Nanotechnology offers great opportunities for sustainable management of degraded soils and using of saline water. The use of green nanoagrochemicals (e.g., nanofertilizers) derived from plant biowastes is highly concerning from an agro-environmental point of view. The impacts of nanoagrochemicals on salt tolerance mech-anisms of Williams banana (Musa spp.) plants under field conditions, particularly in soils with low fertility under salinity stress and low organic matter content, have not yet been verified. Therefore, in this study, a two-year field trial was conducted to investigate the impacts of green nanosilica (GNS) application on the enhancing the salt tolerance of Williams banana plants in arid sandy soil. Banana plants were irrigated with fresh Nile River water (EC = 0.53 dS m(-1)) or saline groundwater (EC = 4.12 dS m(-1)) and sprayed with GNS at doses of 0 mg L-1 (control), 150 mg L-1 (GNS1), and 300 mg L-1 (GNS2) in spring, summer, and autumn. Spraying the saline water-irrigated plants with GNS1 and GNS2 significantly increased the total fruit yield by 30% and 45% in the first year and by 21% and 38% in the second year and reduced the concentrations of Na+ in leaves by 32% and 36%, respectively, compared with the control. Moreover, the foliar application of GNS1 and GNS2 improved the total sugar content in the banana fruits under salinity stress by 42% and 50%, respectively. We assume that GNS application induced an increase in nutrient uptake and that antioxidant and osmoregulation compounds (e.g., proline and soluble carbohydrates) enhanced banana plant tolerance to salinity stress. Although the use of GNS reduced the negative effects of saline irrigation water, banana plants that were irrigated with Nile River water remained significantly better than the saline ground water. In conclusion, the foliar application of GNS improved the productivity and quality of Williams banana fruit in sandy poor soils and enhanced their tolerance to salinity stress, which provides opportunities to expand banana cultivation using saline water in low fertile sandy arid soils. These findings might be an aid for sustainable management of degraded sandy arid soils and reusing of saline water.
查看更多>>摘要：Aerenchyma formation is one of the most effective mechanisms adapted by plants to cope with waterlogging (WL). It which reduces the negative effects of WL by facilitating gas diffusion within roots. To understand the response of cotton roots to WL, hypoxia-tolerant genotype Cx094 and hypoxia-sensitive genotype Wang18 were used in this study. The seedlings of two varieties were treated by three methods: flooding in pots as Treatment 1 (flooding), low oxygen with agar solution as Treatment 2 (flooding + agar) and hypoxia with agar solution and nitrogen gas as Treatment 3 (flooding + agar + N-2). The results showed that in Cx094, the highest proportion of aerenchyma was found in Treatment 2, with no corresponding aerenchyma formation in Wang18. Further studies were carried out in Treatment 2 to check the aerenchyma formation in six cotton accessions and the results showed that aerenchyma only formed in hypoxia-tolerance genotypes, confirming the important role of aerenchyma formation in WL-tolerant genotypes. The unique characteristic of cotton is that four symmetrical aerenchyma were formed under WL stress, and they appeared one by one. We also showed that hypoxia signal induced expression of ACS and ACO genes, resulting more ethylene synthesis in hypoxia-tolerant genotypes. Moreover, ethylene induced reactive oxygen species (ROS) accumulated by up-regulation of RBOHs expression and down-regulation of MT-3a expression. Finally, ROS caused up-regulation of CEL and XET expressions to induce programmed cell death, and result in lysigenous aerenchyma. Exogenous ethylene inhibitor decreased the formation of aerenchyma in Cx094, while ethephon, an ethylene precursor, promote the formation of aerenchyma in Wang18, signifying the important role of ethylene in the formation of aerenchyma in cotton.
查看更多>>摘要：Global warming is asymmetric, with the increase in temperature at night being greater than that during the day. In this study, we conducted night warming treatments using a passive heating device on the wheat variety 'Yangmai 1' grown in culture pots in an experimental field. The night warming treatments were performed from the tillering stage to the jointing stage (NWT-J), from the jointing stage to the booting stage (NWJ-B), and from the booting stage to the anthesis stage (NWB-A). A non-warming treatment was used as a control (NN). Post-anthesis heat (H) stress was performed during the grain-filling stage. The results showed that treatments NWT-J and NWJ-B significantly enhanced grain yield by increasing the 1000-grain weight, while the NWJ-B treatment showed the highest impact. Night warming treatments at early growth stages significantly prevented the grain-yield reduction caused by heat stress during grain filling. NWJ-B treatment increased the sucrose content and sucrose phosphate synthase (SPS) activity of the flag leaves under heat stress during grain filling, which increased the ability of the plants to convert post-anthesis photoassimilates into sucrose, providing a basis for the accumulation of sucrose in the grains. Meanwhile, NWJ-B treatment increased the ability of the plants to assimilate and utilize nitrogen by increasing the nitrogen content and activity of nitrate reductase (NR) and glutamine synthetase (GS) of the flag leaves under heat stress during grain filling. Post-anthesis assimilation products and the activities of the enzymes related to carbon and nitrogen metabolism in wheat plants subjected to night warming treatments maintained at a higher level, which promoted the formation and conversion of proteins and starches in the grains at the late growth stages. Night warming treatments from the jointing to booting stage effectively improved post-anthesis physiological activity and plant productivity, which reduced yield loss caused by heat stress during grain filling.
查看更多>>摘要：Phosphorus (P) utilization by plants is low, which limits crop yields and causes environmental pollution. SAMS1 controls polyamines and ethylene synthesis, and actively responds to various biotic and abiotic stresses. However, how SAMS1 regulates plant P efficiency remains unclear. This study showed that SAMS1-overexpressing improves tomato P efficiency. As a result, overexpression of SAMS1 reduced the accumulation of putrescine and, which induced H2O2 by promoting the conversion of putrescine to spermidine/spermine. This not only facilitated the occurrence of lateral roots under low-P conditions but also promoted the continuous elongation of lateral roots, forming the low-P adaptive root morphological characteristics in tomato plants. In addition to morphological regulation, SAMS1 also promoted root H+-ATPase activity and H+ secretion through polyamines and ethylene signals, enhancing P absorption. However, the phosphatase activity, reutilization of cell wall P, and its distribution to the root was only induced by SAMS1-mediated ethylene signal. Field experiments showed that using SAMS1-overexpressing transgenic rootstocks significantly reduced the input of P fertilizer, promoted plant growth and yield. Together, SAMS1 can promote tomato root growth and P utilization by activating synergistic signals of PAs and Eth.
查看更多>>摘要：Protein legumes are among the most important crops for sustainable agriculture and global food security for decades to come. Unfortunately, they are subject to several abiotic stresses that severely limit their productivity, and this phenomenon is increasing with climate change. New Plant Breeding Technologies (NPBTs) offer novel alternatives to improve the plant performance of crops against such environmental constraints. However, the recalcitrance to transgenesis and in vitro regeneration has delayed such advances for protein legumes. This article reviews recent advances in legume crop biotechnological approaches to improve their tolerance to abiotic stresses including drought, high salinity, heat and cold, and heavy metal stress. In addition to these improvements, obtained mainly through transgenesis, we surveyed the application of tools such as CRISPR/Cas and RNA interference in legumes in a context of abiotic stress tolerance, and suggested a path to follow for gene control by these tools in legume plants, organs, or cells. Furthermore, we also discussed promising molecular targets, perspectives, and the way ahead for enhancing abiotic stress tolerance.
查看更多>>摘要：Triterpenoids and flavonoids from licorice (Glycyrrhiza uralensis Fisch.) are known to have a wide range of applications in the pharmaceutical, skin care, and food industries. The effects of various types of abiotic stresses and associated phytohormones -polyethylene glycol, sodium chloride, ultraviolet, cadmium, abscisic acid, and methyl jasmonate -on both the content of these secondary metabolites and the transcript levels of genes encoding enzymes of important biosynthetic pathways were evaluated in hydroponic seedlings of G. uralensis. In these treatments, abscisic acid induced a substantial increase in the levels of the four active compounds, compared to the control. Analysis of the expression of genes involved in the biosynthetic pathways of these compounds, such as FPPS, showed that their transcript levels were significantly up-regulated in the four stresses. These findings suggested that the multi-stress superposition pattern of the content of active compounds and the gene expression of their biosynthetic pathways may provide insights to explore the management of secondary metabolite synthesis pathways in medicinal plants. It could facilitate a better understanding of the formation patterns of active compounds in licorice in artificial cultivation. Further insights may also be provided to increase the yield of these high value components.
查看更多>>摘要：Maintaining assimilates metabolism is critical for root and shoot normal function, especially during drought. However, little is known about how plants coordinate assimilates transport and internal root and shoot assimilates usage under drought. To test these objectives, a greenhouse experiment was carried out in which two cotton cultivars (Dexiamian 1 and Yuzaomian 9110) with varied drought tolerance were subjected to a continuous soil water deficit. We used stable-isotope labeling to examine the changes in assimilates allocation, as well as the responses of metabolic activities in the root and leaf to drought. According to the findings, root nitrogen absorption was reduced as a result of insufficient ATP supply and the down-regulated GhNPF4.6. Further, the limited root nitrate absorption and nitrate transport from root to shoot reduced leaf nitrogen accumulation. Moreover, less proportion of nitrogen invested in photosynthetic apparatus under drought limited the leaf photosynthetic performance. Drought suppressed leaf CO2 fixation and photosynthates export, but the relative amount of photosynthates allocated in root increased due to the increasing expression of sucrose transporters. However, the stunted respiratory metabolism limited root function although the carbohydrates were sufficient. We conclude that drought disrupts assimilate partition between root and shoot, restricts root carbohydrates use, and reduces leaf photosynthetic nitrogen utilization, resulting in a functional imbalance between root and shoot.
查看更多>>摘要：Green onion is an herbaceous plant of the genus Allium in the Liliaceae family, with complex genomes and transcripts. The blue spectrum is necessary for plant photosynthesis. To explore the potential impact of blue light on green onions, we cultivated green onion seedlings under the light intensity of 500 +/- 10 mu mol.photons.m(-2).s(-1) white light (W), white-blue combination 3:1 (BW) and monochromatic blue light (B) LED light source. We investigated the diversity of the green onion transcriptome and the differences in transcripts among treatments using a combination of long-read length sequencing and RNA-seq, aiming to assess the effects of supplemental blue light (BW) on the growth and photosynthesis of green onion seedlings. The results showed that BW significantly increased seedling growth and photosynthesis, while B significantly decreased photosynthetic rate and fenestrated tissue layer. Compared to W, 327 and 386 differentially expressed genes (DEGs) were identified under BW and B. DEGs under 3 light conditions were related to photosynthesis, carbon metabolism, photosynthesis antenna proteins, glyoxylate and dicarboxylate metabolism, sulfur metabolism, porphyrin and chlorophyll metabolism, phototransduction, biosynthesis of amino acids, RNA transport, carbon fixation in photosynthetic organisms, etc. pathways were closely related. Our results showed that white LEDs with supplemental blue light significantly improves the growth of green onion seedlings by regulating photosynthesis related genes compared with white light. In conclusion, white LEDs with supplemental blue light could promote the growth of green onion in a controlled environment.
查看更多>>摘要：Roots exhibit positive hydrotropism in response to soil moisture gradients in arid conditions. However, the mechanisms that regulate hydrotropism are yet to be elucidated. Ca2+ is involved in this response, but the molecular factors that interact with Ca2+ are currently unknown. To understand the role of Ca2+ in hydrotropism, as well as to identify proteins that are involved in this process, we examined the physiology of Arabidopsis thaliana seedlings cultured in Ca2+-free medium. Treatment with cytosolic and apoplastic Ca2+ chelators triggered an increase in hydrotropic root bending, which became more pronounced during the latter stages of the hydrotropic response. Furthermore, we found that the phenotypes of mutants defective in OSCA1.1, a mecha-nosensitive Ca2+ channel, resembled those of wild-type seedlings treated with Ca2+ chelators. Although treatment with Ca2+ chelators also affected root gravitropism, no significant differences in root gravitropism were observed in osca1 mutants, suggesting that OSCA1.1 has a specific function in root hydrotropism. Moreover, transcript level of MIZ1 in OSCA1.1 knockout mutant was higher than that of wild type, specifically at latter stages of the hydrotropic response. Double mutants that carry miz1-1 or miz2 alleles in addition to the osca1 knockout allele lacked hydrotropic response, the phenotypes of which were resembled those of miz1-1 or miz2 single mutants. Our results suggest that OSCA1.1 functions within the same signaling pathway as MIZ1 and MIZ2, and that OSCA1.1-mediated Ca2+ influx across the plasma membrane is required to regulate hydrotropic root bending by regulating MIZ1 expression at the latter stages.
NSTL
Elsevier