Coronatine (COR) is a phytotoxin produced by
Pseudomonas syringae
and is a functional analogue of the bioactive hormone JA-Ile, which is widely involved in plant defence responses. In this study, we ...explored the effects of exogenous applications of COR on tobacco plants under polyethylene glycol-induced drought stress. Compared with control (CK), COR-treated tobacco plants exhibited higher leaf relative water content and better photosynthetic performance under drought exposure. Ultrastructural examination revealed that drought led to stomatal closure and disorganization of granum stacking in the chloroplasts (with obvious accumulation of plastoglobuli), and mitochondria in the CK samples presented injured cristae. In the leaf tissue of the COR-treated plants, regularly stacked granum thylakoids, few plastoglobuli and intact mitochondrial membranes and cristae were observed. Totals of 1803 and 6207 differentially expressed genes (DEGs) were identified between the samples from the COR-treated and CK plants under well-watered and drought conditions. Functional annotation analysis revealed that these DEGs were involved mainly in plant hormone signal transduction, cellular carbohydrate metabolic processes and photosynthesis processes. Six hundred forty transcription factor genes were also identified among the DEGs. This study provides a global view of COR-induced drought stress tolerance in tobacco from both physiological and transcriptional aspects.
In this study, Bi
2
O
3
nanoparticles are prepared via an impregnation method and modified using multi-walled carbon nanotubes (MWCNTs) and PW
12
. XRD reveals that the prepared Bi
2
O
3
corresponded ...to the monoclinic
α
-phase. SEM results reveal that the composite consists of a series of nanosheets with flower-like structures. In this study, malachite green (MG) is used as a simulated contaminant to test the degradation capability of the compound under sunlight, and the effect of PW
12
doping on the photocatalytic properties of the sample is investigated. The results show that the degradation kinetic constant of 0.3 PW
12
/MWCNTs/Bi
2
O
3
(0.8125 h
−1
) is about 3 times that of Bi
2
O
3
(0.2767 h
−1
). The ternary complex containing 30% PW
12
has a degradation rate of 95% in 2.5 h. h
+
and
·
O
2
-
were the major active species in the photocatalytic degradation of MG.
Low temperature represents a key environmental stress adversely affects rice growth and productivity worldwide. The application of cold resistance regulators is an effective way to enhance crop cold ...tolerance and yields. Coronatine (COR), a structural and functional analog of JA, plays a crucial role in plant stress response. In order to investigate the role of COR in alleviating cold stress of rice, the cold-resistant variety Nipponbare and cold-sensitive variety Guichao2 were used to study. The results indicated that 0.01 μmol L
−1
COR possessed the most favorable cold resistance potential. Under cold stress conditions, 0.01 μmol L
−1
COR treatment promoted the germination of rice seeds, increased the accumulation of osmotic adjustment protective substances, and mitigated the toxic effect of reactive oxygen species on cells. Additionally, COR induced the expression of cold-responsive genes, including
OsCBF1
,
OsCBF2
,
OsCBF3
and
OsMYB2
. Overall, COR regulated the antioxidative defense system and
CBF
genes expression of rice to withstand cold stress.
Maize yield is limited by water deficit in the arid and semiarid regions of China. Conserving water and enhancing crop water productivity are inevitable requirements for the sustainable development ...of water efficient agriculture. Plant growth regulators (PGRs) play important roles in maize water stress tolerance. In this study, we investigated the effect of plant growth regulator-brazide, a functional analog of brassinolide (BR), on maize water stress resistance through a two-year (2020–2021) field experiment. The experiment included four water treatments (I100: 4012 m3 ha−1; I80: 3210 m3 ha−1; I60: 2407 m3 ha−1; I40: 1605 m3 ha−1), four PGR concentrations (CK: water; Bra: 0.1 μmol L−1 14-hydroxylated brassinosteroid; B1: 0.1 μmol L−1 brazide; B2: 1 μmol L−1 brazide; B3: 10 μmol L−1 brazide). The results showed that deficit irrigation (I60 and I40) decreased soil water content (SWC), photosynthetic rate (Pn), leaf area index (LAI), aboveground biomass (AB) and yield, but improved crop water productivity (WPc). Under deficit irrigation conditions, 1 μmol L−1 brazide application also increased dry matter accumulation and grain yield, a result attributed to improvement of the photosynthetic rate and increases in the root bleeding saps, water productivity. 1 μmol L−1 Brazide application reduced bare tip length, increasing kernel number per ear, thereby increased the yield of I60 and I40 by 15.1% and 11.4% (p ≤ 0.05; 2020), 16.4% and 20.4% (p ≤ 0.001; 2021), respectively. Path analysis showed brazide improved final yields by increasing thousand grain weight (TGW), photosynthetic rate (Pn) and WPc under deficit irrigation. The increase in TGW with brazide treatment was primarily attributed to the increase of Pn. Overall, Brazide increased maize drought resistance mainly by increasing Pn and WPc, with 1 μmol L−1 brazide as an optimal concentration.
•A new plant growth regulator, Brazide, was evaluated in maize.•Brazide increased photosynthetic rate and WUE under deficit irrigation.•Application of brazide improved maize growth and grain yield under deficit irrigation.•1 μmol L−1 brazide as an optimal concentration for maize in arid region of Northwest China.
Silicon (Si) may be involved in metabolic, physiological, and/or structural activity in higher plants exposed to abiotic and biotic stresses. This has not yet been determined due to the absence of ...direct evidence that it is part of the molecule of an essential plant constituent or metabolite. The aim of this study was to investigate the effect of silicon on soybean seedlings under drought and ultraviolet-B (UV-B) radiation stresses. The relative leaf water content (RWC), which was the main factor resulting in reduced growth in response to drought, increased 19.0% and 30.0% with Si application under drought and drought
+
UV-B stresses, respectively. Under UV-B radiation, the anthocyanin and phenol levels decreased 91.5% and 10.0% in the treatment of Si. Ultraviolet-B radiation and drought stress caused great membrane damage, as assessed by lipid peroxidation and osmolyte leakage, but Si application significantly reduced the membrane damage. Catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and hydrogen peroxide were observed under stress conditions. Proline increased primarily in drought-stressed seedlings and may be the drought-induced factor with a protective role in response to UV-B and silicon. Photosynthesis (
P
N) increased following Si application by 21.0%, 18.3% and 21.5% under UV-B radiation, drought and the combination, respectively. The physiological and biochemical parameters measured indicated that the UV-B light had more adverse effects on growth of soybean seedlings than drought, but the data also showed that Si could alleviate seedling damage under these stress conditions.
Salt stress negatively affects maize growth and yield. Application of plant growth regulator is an effective way to improve crop salt tolerance, therefore reducing yield loss by salt stress. Here, we ...used a novel plant growth regulator B2, which is a functional analogue of ABA. With the aim to determine whether B2 alleviates salt stress on maize, we studied its function under hydroponic conditions. When the second leaf was fully developed, it was pretreated with 100 µM ABA, 0.01 µM B2, 0.1 µM B2, and 1 µM B2, independently. After 5 days treatment, NaCl was added into the nutrient solution for salt stress. Our results showed that B2 could enhance salt tolerance in maize, especially when the concentration was 1.0 µMol·L
. Exogenous application of B2 significantly enhanced root growth, and the root/shoot ratio increased by 7.6% after 6 days treatment under salt stress. Compared with control, the ABA level also decreased by 31% after 6 days, which might have resulted in the root development. What is more, B2 maintained higher photosynthetic capacity in maize leaves under salt stress conditions and increased the activity of antioxidant enzymes and decreased the generation rate of reactive oxygen species by 16.48%. On the other hand, B2 can enhance its water absorption ability by increasing the expression of aquaporin genes
and
. In conclusion, the novel plant growth regulator B2 can effectively improve the salt tolerance in maize.
Low grain water content (GWC) at harvest of maize (Zea mays L.) is essential for mechanical harvesting, transportation and storage. Grain drying rate (GDR) is a key determinant of GWC. Many ...quantitative trait locus (QTLs) related to GDR and GWC have been reported, however, the confidence interval (CI) of these QTLs are too large and few QTLs has been fine-mapped or even been cloned. Meta-QTL (MQTL) analysis is an effective method to integrate QTLs information in independent populations, which helps to understand the genetic structure of quantitative traits. In this study, MQTL analysis was performed using 282 QTLs from 25 experiments related GDR and GWC. Totally, 11 and 34 MQTLs were found to be associated with GDR and GWC, respectively. The average CI of GDR and GWC MQTLs was 24.44 and 22.13 cM which reduced the 57 and 65% compared to the average QTL interval for initial GDR and GWC QTL, respectively. Finally, 1494 and 5011 candidate genes related to GDR and GWC were identified in MQTL intervals, respectively. Among these genes, there are 48 genes related to hormone metabolism. Our studies combined traditional QTL analyses, genome-wide association study and RNA-seq to analysis major locus for regulating GWC in maize.
Strigolactones (SLs) are a class of plant hormones and rhizosphere communication signals of great interest. They perform diverse biological functions including the stimulation of parasitic seed ...germination and phytohormonal activity. However, their practical use is limited by their low abundance and complex structure, which requires simpler SL analogues and mimics with maintained biological function. Here, new, hybrid-type SL mimics were designed, derived from Cinnamic amide, a new potential plant growth regulator with good germination and rooting-promoting activities. Bioassay results indicated that compound
not only displayed good germination activity against the parasitic weed
with an EC
value of 2.36 × 10
M, but also exhibited significant inhibitory activity against
root growth and lateral root formation, as well as promoting root hair elongation, similar to the action of GR24. Further morphological experiments on
mutants revealed that
possessed SL-like physiological functions. Furthermore, molecular docking studies indicated that the binding mode of
was similar to that of GR24 in the active site of OsD14. This work provides valuable clues for the discovery of novel SL mimics.
MicroRNA (miRNA) plays vital roles in the regulation of both plant architecture and stress resistance through cleavage or translation inhibition of the target messenger RNAs (mRNAs). However, ...miRNA-induced gene silencing remains a major challenge in vivo due to the low delivery efficiency and instability of miRNA, thus an efficient and simple method is urgently needed for miRNA transformation. Previous researches have constructed a star polycation (SPc)-mediated transdermal double-stranded RNA (dsRNA) delivery system, achieving efficient dsRNA delivery and gene silencing in insect pests.
Here, we tested SPc-based platform for direct delivery of double-stranded precursor miRNA (ds-MIRNA) into protoplasts and plants. The results showed that SPc could assemble with ds-MIRNA through electrostatic interaction to form nano-sized ds-MIRNA/SPc complex. The complex could penetrate the root cortex and be systematically transported through the vascular tissue in seedlings of Arabidopsis and maize. Meanwhile, the complex could up-regulate the expression of endocytosis-related genes in both protoplasts and plants to promote the cellular uptake. Furthermore, the SPc-delivered ds-MIRNA could efficiently increase mature miRNA amount to suppress the target gene expression, and the similar phenotypes of Arabidopsis and maize were observed compared to the transgenic plants overexpressing miRNA.
To our knowledge, we report the first construction and application of star polycation nanocarrier-based platform for miRNA delivery in plants, which explores a new enable approach of plant biotechnology with efficient transformation for agricultural application.
Drought stress negatively affects wheat growth and yield. Application of drought agent is an effective way to improve crop drought tolerance, therefore increasing crop yield. Based on the structure ...of abscisic acid (ABA), Pyrabactin and coronatine (COR), we designed the target compound B2. To investigate the function of B2 in alleviating drought stress on wheat, the drought-resistant variety ND212 and drought-sensitive variety LX99 were used under hydroponic conditions. The results showed that B2 had a similar function with ABA, especially 0.01 μmol·L
B2. Under drought stress conditions, 0.01 μmol·L
B2 increased the water content of wheat, enhanced the osmotic adjustment ability of leaves, and reduced the toxicity of reactive oxygen species on cells. What's more, 0.01 μmol·L
B2 improved the expression level of ABA-responsive genes TaSnRK2.4 and TaMYB3R1. It also improved the expression level of drought-responsive genes TaSRHP and TaERF3. Taken together, B2 enhanced drought tolerance in wheat by activating ABA signaling pathway.
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