Functional Plant Biology最新文献

Drying wheat (Triticum durum ) seeds within their spikes may improve the seed desiccation tolerance. This study aimed to understand the effect of drying wheat seeds within their spikes on their desiccation tolerance in association with GABA (γ-aminobutyric acid) content, malondialdehyde (MDA), the expression of three dehydrin genes (dhn , wcor , dreb ) during seed development. Seeds of wheat variety 'Hourani-Nawawi' were harvested at five developmental stages: (1) milk (ML); (2) soft dough (SD); (3) hard dough (HD); (4) physiological maturity (PM); and (5) harvest maturity (HM) and dried either attached to or detached from their spikes. Drying the seeds attached to their spikes improved desiccation tolerance, speed of germination, and seedling length at ML stage. Before drying (freshly harvested), the seeds harvested at ML and HM had higher GABA than those at SD, HD, and PM. The attached-dried seeds had higher GABA content from ML to PM than at HM, and higher glutamate content at ML, SD, and HD than at the PM stage. Detached-dried seeds had the highest alanine at ML and PM. Attached-dried seeds had lower MDA than detached-dried seeds. Expression of dhn was highest in freshly-harvested and attached-dried seeds at SD. Highest expression of wcor in the attached-dried seeds was detected at SD and HM. Drying the seeds within their spikes increased the expression of dreb gene compared with the freshly-harvested seeds, except at the HD stage. In conclusion, drying the seeds within their spikes enhanced seed germination in association with higher GABA, lower MDA, and higher gene expression.

Rice (Oryza sativa ) is a crucial staple crop worldwide, providing nutrition to more than half of the global population. Nonetheless, the sustainability of grain production is increasingly jeopardized by both biotic and abiotic stressors exacerbated by climate change, which increases the crop's rvulnerability to pests and diseases. Genome-editing by clustered regularly interspaced short palindromic repeats and CRISPR-associated Protein 9 (CRISPR-Cas9) presents a potential solution for enhancing rice productivity and resilience under climatic stress. This technology can alter a plant's genetic components without the introduction of foreign DNA or genes. It has become one of the most extensively used approaches for discovering new gene functions and creating novel varieties that exhibit a higher tolerance to both abiotic and biotic stresses, herbicide resistance, and improved yield production. This study examines numerous CRISPR-Cas9-based genome-editing techniques for gene knockout, gene knock-in, multiplexing for simultaneous disruption of multiple genes, base-editing, and prime-editing. This review elucidates the application of genome-editing technologies to enhance rice production by directly targeting yield-related genes or indirectly modulating numerous abiotic and biotic stress-responsive genes. We highlight the need to integrate genetic advancements with conventional and advanced agricultural methods to create rice varieties that are resilient to stresses, thereby safeguarding food security and promoting agricultural sustainability amid climatic concerns.

Detrimental effects of terminal heat stress could be mitigated by exogenous application of synthetic compounds by preserving cell membrane integrity and protecting against oxidative damage. A field experiment was conducted to test the application of seven synthetic compounds on wheat growth traits: (1) thiourea (20 mM and 40mM); (2) potassium nitrate (1% and 2%); (3) sodium nitroprusside (400 μg mL-1 and 800μg mL-1 ); (4) dithiothreitol (25 ppm and 50ppm); (5) salicylic acid (100 ppm and 200ppm); (6) thioglycolic acid (200 ppm and 500ppm); and (7) putrescine (4 mM and 6mM). These compounds were applied at the anthesis and grain-filling stages to enhance physio-biochemical traits and yield attributes of wheat (Triticum aestivum ) cvs GW-11 and GW-496 under terminal heat stress. The results indicated that GW-11 plants treated with 100ppm salicylic acid exhibited significant improvements (P ≤0.05) in canopy temperature depression, proline content, total chlorophyll content, and the membrane stability index. Compared with the control treatment, foliar application of 100ppm salicylic acid at both stages caused increases in grain yield (19.5%), followed by a 14% increase with 4mM putrescine. These yield improvements were attributed to higher grains per spike, more effective tillers, and greater 1000-grain weight, reflecting enhanced sink capacity and grain development under stress. Consequently, the foliage application of 100ppm salicylic acid at the anthesis and grain-filling stages is recommended to improve late-sown wheat productivity and reduce terminal heat stress.

Remote sensing of stressor action on plants is an important step of their protection. Measurement of photochemical reflectance index (PRI) can be used to detect action of stressors including salinization; potentially, a small-scale spatial heterogeneity of PRI (within leaf or its part) can be an indicator of this action. The current work was devoted to analysis of sensitivity of the small-scale heterogeneity in PRI and in the reflected light intensity at 530nm (approximately corresponding to the measuring wavelength for PRI) in leaves of pea (Pisum sativum ) plants to action of salinization. Plants were cultivated under controlled conditions of a vegetation room and under open-air conditions. It was shown that both the standard deviation of PRI and coefficient of variation of the reflected light intensity at 530nm were sensitive to action of salinization on plants. Moreover, this variation coefficient was negatively corelated to the potential quantum yield of PSII; i.e. increasing the coefficient could be used to estimate decreasing this yield caused by photodamage of PSII under salinization. Our results show that the small-scale spatial heterogeneity in PRI and the reflected light intensity at 530nm can be used as additional tools of the remote sensing of plant responses under action of salinization.

Plant stems grow towards the incident light in response to unilateral blue light to optimize photosynthesis. However, our findings reveal that unilateral high-intensity blue light (HBL) triggers backlit lodging in etiolated cotton (Gossypium hirsutum ) hypocotyls when they are pulled approximately 1.5cm from the soil. Phenotypic analysis indicated that stomata on the lit side were open, while those on the shaded side were closed under unilateral HBL. To investigate the relationship between stomatal movement and backlit lodging, we applied abscisic acid (ABA), hydrogen peroxide (H2 O2 ), and lanthanum chloride (LaCl3 ) to the lit side, and cytokinins (6-BA) and ascorbic acid (ASA) to the shaded side. Results showed that all these treatments inhibited the backlit lodging phenomenon, specifically, ABA, H2 O2 , and LaCl3 reduced stomatal opening on the lit side, while 6-BA and ASA enhanced stomatal opening on the shade side. These results demonstrate that HBL-induced asymmetrical stomatal opening on the lit and shade side of hypocotyl supports the backlit lodging phenomenon. Notably, maize (Zea mays ), which lack stomata in the hypocotyl did not exhibit HBL-induced backlit lodging, whereas soybean (Glycine max ), which has stomata in its etiolated hypocotyl, displayed a similar phenotype to that of cotton. Additionally, while both red light and low-intensity blue light (LBL) can induce stomatal opening, they do not trigger the backlit lodging phenomenon. These findings suggest that backlit lodging is a unique HBL-dependent response, but the mechanism need further investigation.

The NHX1 gene encodes a Na+ /H+ antiporter located in the tonoplast membrane, which plays critical role in regulating plant salt tolerance. It is also involved in the uptake and accumulation of K in plants; however, its precise mechanism is unknown. In this research, we elucidated the physiological basis underlying the increases in K content induced by NHX1 . We evaluated main agronomic traits, leaf K content, K+ uptake kinetics, and root morphological and physiological characteristics from field-planted and hydroponic plants. We included a wild-type tobacco (Nicotiana tabacum ) variety (K326) and three transgenic tobacco lines (NK7, NK9, NK10) that overexpress AtNHX1 from Arabidopsis thaliana . Results demonstrated that the agronomic performance of the AtNHX1 -overexpressing tobacco lines was similar to K326 in field and hydroponic settings. The three AtNHX1 -overexpressing tobacco lines had significantly higher leaf K contents than K326. Under hydroponic condition, enhanced K uptake capacity and a larger maximum K uptake rate were seen in AtNHX1 -overexpressing tobacco lines. AtNHX1 -overexpressing lines also exhibited significantly superior root morphological and physiological traits relative to K326, including root biomass, root volume, absorption area, root activity, cation exchange capacity, soluble protein content, and H+ -ATPase activity. Overexpression of AtNHX1 in tobacco significantly improves the K uptake and accumulation. Therefore, leaf K content greatly increased in these transgenic lines in the end. Our findings strongly suggest that AtNHX1 overexpression increased leaf K content by boosting the capacity of enriching K in tobacco roots, thereby advancing the understanding of the function of AtNHX1 .

Plants often experience variations in light intensity, referred to as light stress, that negatively impact important aspects of plant growth and development, including photosynthesis and antioxidant system. The photosynthetic machinery is susceptible to these disturbances, especially photosystem II and its reaction centers. We aimed to evaluate the role of brassinosteriod in plants under both high and low light conditions by examining various physiological parameters such as photosynthetic efficiency, pigment levels, and enzymatic activity of various antioxidant enzymes in one month old tomato plants. We investigated various chlorophyll fluorescence parameters under low light (LL) and high light (HL) conditions and the associated gene expression related to photosynthesis, including plastocyanin, ferredoxin, and photosystem II oxygen-evolving enhancer protein 3 (PsbQ). Our results indicate that exogenous brassinosteroid application considerably increased tolerance to both high and low light stress in 4-week-old tomato as treated plants displayed enhanced photosynthesis, reduced oxidative damage, and increased antioxidant enzyme activity in comparison to control plants. Furthermore, brassinosteroid treatment enhanced the expression of genes associated with antioxidant pathways, which significantly contributed to the recovery of chlorophyll fluorescence parameters crucial for plant growth and development. Our results provide valuable insights into how brassinosteroid reduces light-induced stress in tomato plants.

In soybean (Glycine max ), limiting whole-plant transpiration rate (TR) response to increasing vapor pressure deficit (VPD) has been associated with the 'slow-wilting' phenotype and with water-conservation enabling higher yields under terminal drought. Despite the promise of this trait, it is still unknown whether it has a genetic basis in soybean, a challenge limiting the prospects of breeding climate-resilient varieties. Here, we present the results of a first attempt at a high-throughput phenotyping of TR and stomatal conductance response curves to increasing VPD conducted on a soybean mapping population consisting of 140 recombinant inbred lines (RIL). This effort was conducted over two consecutive years, using a controlled-environment, gravimetric phenotyping platform that enabled characterizing 900 plants for these responses, yielding regression parameters (R 2 from 0.92 to 0.99) that were used for genetic mapping. Several quantitative trait loci (QTL) were identified for these parameters on chromosomes (Ch) 4, 6, and 10, including a VPD-conditional QTL on Ch 4 and a 'constitutive' QTL controlling all parameters on Ch 6. This study demonstrated for the first time that canopy water use in response to rising VPD has a genetic basis in soybean, opening novel avenues for identifying alleles enabling water conservation under current and future climate scenarios.

Previous research from our lab demonstrated that hypergravity that can be simulated using tabletop centrifuges, offering significant benefits to crop plants. Hypergravity enhances seedling vigor and growth parameters in bread wheat (Triticum aestivum ) variety UAS 375. This enhanced root growth phenotype is believed to boost abiotic stress tolerance by facilitating deeper access to water and nutrients from the soil. This study investigated whether hypergravity-induced root growth enhancements could offer resilience to induced drought and salt stress, and whether such benefits would extend across other wheat genotypes. Hypergravity (10g for 12h) conferred significant tolerance to simulated drought and salt stress, evidenced by improved seedling growth parameters as well as increased chlorophyll content and proline accumulation in response to hypergravity followed by stress challenge, compared to stress challenge alone. Liquid chromatography with tandem mass spectrometry indicated dynamic phytohormone modulation, and quantitative reverse transcription polymerase chain reaction data revealed significant alterations in the expression of genes associated with antioxidant enzymes and abiotic stresses. Thus, this study further supports the view that hypergravity boosts abiotic stress resilience through genetic and hormonal dynamics. Notably, these effects were consistent across genotypes. In conclusion, this study provides evidence that hypergravity can effectively improve resilience against seedling abiotic stresses in wheat.

Senescence represents a developmentally orchestrated and precisely regulated cascade of events, culminating in the abscission of plant organs and ultimately leading to the demise of the plant or its constituent parts. In this study, we observed that senescence in cut Lilium tigrinum flowers is induced by elevated ABA levels and the hyperactivation of lipoxygenase (LOX) activity. This cascade increased ROS concentrations, heightened oxidative damage, and disrupted cellular redox equilibrium. This was evidenced by elevated lipid peroxidation, attenuated antioxidant machinery, and reduced membrane stability index (MSI). Despite its known role in delaying flower senescence, the specific biochemical and molecular mechanisms by which nitric oxide (NO) regulates senescence in cut L. tigrinum flowers are not fully elucidated. Specifically, the interactions between NO signaling and ABA metabolism, the regulation of protease activity, and the influence of NO-mediated ROS scavenging, senescence-associated gene expression requires further exploration. Exogenous application of sodium nitroprusside (SNP), a source of NO, mitigated senescence in L. tigrinum cut flowers by upregulating the activity of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and reducing the LOX activity, an indicator of lipid peroxidation. SNP treatment also downregulated the relative expression of senescence-associated gene (SAG12 ),lipoxygenase 1 (LOX1 ), and abscisic aldehyde oxidase 3 (AAO3 ). NO also upregulated defender against apoptotic death 1 (DAD1 ) expression correlated with minimized protease activity and reduced α-amino acid content in SNP-treated tepals. This regulation was accompanied by increased contents of sugars, proteins and phenols and reduced abscisic acid content, which collectively delayed the senesecence and enhanced the longevity of L. tigrinum cut flowers. This study demonstrates that exogenous SNP application can effectively mitigate senescence in cut L. tigrinum flowers by modulating antioxidant enzyme activities, reducing oxidative stress, and regulating the expression of key senescence-associated genes. This study unravels the complex molecular networks involved in NO-mediated senescence delay, which may lead to the development of innovative approaches for improving flower longevity.