Gibberellin Treatment Research Articles

PavSPLs are key regulators of growth, development, and stress response in sweet cherry

SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) genes are plant-specific transcription factors essential for plant growth, development, and stress responses; however, their roles in sweet cherry are not well understood. In this study, we identified and isolated 16 SPL genes from the sweet cherry genome, categorizing them into five subfamilies, with 12 PavSPLs predicted as miR156 targets. The promoter regions of PavSPLs contain cis-elements associated with light, stress, and phytohormone responses, indicating their role in biological processes and abiotic stress responses. Seasonal expression analysis showed that PavSPL regulates sweet cherry recovery after dormancy. Gibberellin (GA) treatment reduced PavSPL expression, indicating its role in GA-mediated processes. Overexpression of PavSPL14 in Arabidopsis thaliana resulted in earlier flowering, increased plant height, and enhanced growth. Yeast two-hybrid assays revealed an interaction between PavSPL14 and DELLA protein PavDWARF8, suggesting the involvement of PavSPLs in GA-regulated processes through protein interactions. These findings lay the groundwork for future studies on PavSPL function in sweet cherry.

Overexpression of two DELLA subfamily genes MiSLR1 and MiSLR2 from mango promotes early flowering and enhances abiotic stress tolerance in Arabidopsis

Gibberellic acids (GAs) are a group of endogenous phytohormones that play important roles in plant growth and development. SLENDER RICE (SLR) serves as a vital component of the DELLA gene family, which plays an irreplaceable role in regulating plant flowering and height, as well as stress responses. SLR gene has not been reported in mango, and its function is unknown. In present study, two DELLA subfamily genes MiSLR1 and MiSLR2 were identified from mango. MiSLR1 and MiSLR2 were highly expressed in the stems of the juvenile stage, but were expressed at a low level in flower buds and flowers. Gibberellin treatment could up-regulate the expression of MiSLR1 and MiSLR2 genes, but gibberellin biosynthesis inhibitor prohexadione-calcium (Pro-Ca) and paclobutrazol (PAC) treatments significantly down-regulated the expression of MiSLR1, while MiSLR2 was up-regulated. The expression levels of MiSLR1 and MiSLR2 were up-regulated under both salt and drought treatments. Overexpression of MiSLR1 and MiSLR2 genes significantly resulted early flowering in transgenic Arabidopsis and significantly up-regulated the expression levels of endogenous flower-related genes, such as SUPPRESSOR OF CONSTANS1 (SOC1), APETALA1 (AP1), and FRUITFULL (FUL). Interestingly, MiSLR1 significantly reduced the height of transgenic plants, while MiSLR2 gene increased. Overexpression of MiSLR1 and MiSLR2 increased seed germination rate, root length and survival rate of transgenic plants under salt and drought stress. Physiological and biochemical detection showed that the contents of proline (Pro) and superoxide dismutase (SOD) were significantly increased, while the contents of malondialdehyde (MDA) and H2O2 were significantly decreased. Additionally, protein interaction analysis revealed that MiSLR1 and MiSLR2 interacted with several flowering-related and GA-related proteins. The interaction between MiSLR with MiGF14 and MiSOC1 proteins was found for the first time. Taken together, the data showed that MiSLR1 and MiSLR2 in transgenic Arabidopsis both regulated the flowering time and plant height, while also acting as positive regulators of abiotic stress responses.

Effects of Foliar Application of Plant Growth Regulators on germination Enzyme Activities in the Wild Barely (<i>Hordeum spontanium</i>)

Wild barley, from the Gramineae family, due to primary dormancy, is one of the most important weed in wheat. We hypothesized that foliar application of plant growth regulators (PGRs) affects breaking dormancy in wild barley via germination enzyme activities and seed germination immediately on the mother plant to reduce soil seed bank. To measure the activity of enzymes alpha-amylase, protease, and invertase, two experiments were conducted based on a completely randomized design with 3 replications at the University of Kurdistan farm and Laboratory in 2016 and 2017. In the first experiment the highest and lowest alpha-amylase activity was obtained in gibberellin treatment at a concentration of 100 mgL<sup>-1</sup> and control treatment on hull seed, respectively. The activity of protease enzyme in applied treatments had a similar trend as 100 mgL<sup>-1</sup> of gibberellin treatment. The highest and the lowest protease activities were 12.62 and 3.82 Ug<sup>-1</sup> related to gibberellin treatment at a concentration of 100 mgL<sup>-1</sup> and control treatment, respectively. The second experiment was conducted to investigate the effect of time of PGRs foliar application on the parent plant on the activity of enzymes. Gibberellin 100 mg<sup>-1</sup>, salicylic acid 0.5, and 1 mM treatment on the mother plant produced the highest alpha-amylase, invertase, and protease activities when used after 50 days after pollination, there was no uniform trend in enzymes activity. In general, gibberellin treatment at a concentration of 100 mgL<sup>-1</sup> 50 days after pollination produced the highest activities of germination enzyme activities.

A gibberellin-assisted study of the transcriptional and hormonal changes occurring at floral transition in peach buds (Prunus persica L. Batsch)

BackgroundFlower load in peach is an important determinant of final fruit quality and is subjected to cost-effective agronomical practices, such as the thinning, to finely balance the sink-source relationships within the tree and drive the optimal amount of assimilates to the fruits. Floral transition in peach buds occurs as a result of the integration of specific environmental signals, such as light and temperature, into the endogenous pathways that induce the meristem to pass from vegetative to reproductive growth. The cross talk and integration of the different players, such as the genes and the hormones, are still partially unknown. In the present research, transcriptomics and hormone profiling were applied on bud samples at different developmental stages. A gibberellin treatment was used as a tool to identify the different phases of floral transition and characterize the bud sensitivity to gibberellins in terms of inhibition of floral transition.ResultsTreatments with gibberellins showed different efficacies and pointed out a timeframe of maximum inhibition of floral transition in peach buds. Contextually, APETALA1 gene expression was shown to be a reliable marker of gibberellin efficacy in controlling this process. RNA-Seq transcriptomic analyses allowed to identify specific genes dealing with ROS, cell cycle, T6P, floral induction control and other processes, which are correlated with the bud sensitivity to gibberellins and possibly involved in bud development during its transition to the reproductive stage. Transcriptomic data integrated with the quantification of the main bioactive hormones in the bud allowed to identify the main hormonal regulators of floral transition in peach, with a pivotal role played by endogenous gibberellins and cytokinins.ConclusionsThe peach bud undergoes different levels of receptivity to gibberellin inhibition. The stage with maximum responsiveness corresponded to a transcriptional and hormonal crossroad, involving both flowering inhibitors and inductors. Endogenous gibberellin levels increased only at the latest developmental stage, when floral transition was already partially achieved, and the bud was less sensitive to exogenous treatments. A physiological model summarizes the main findings and suggests new research ideas to improve our knowledge about floral transition in peach.

Genome-wide identification and expression analysis of the Eriobotrya japonica TIFY gene family reveals its functional diversity under abiotic stress conditions

BackgroundPlant-specific TIFY proteins are widely found in terrestrial plants and play important roles in plant adversity responses. Although the genome of loquat at the chromosome level has been published, studies on the TIFY family in loquat are lacking. Therefore, the EjTIFY gene family was bioinformatically analyzed by constructing a phylogenetic tree, chromosomal localization, gene structure, and adversity expression profiling in this study.ResultsTwenty-six EjTIFY genes were identified and categorized into four subfamilies (ZML, JAZ, PPD, and TIFY) based on their structural domains. Twenty-four EjTIFY genes were irregularly distributed on 11 of the 17 chromosomes, and the remaining two genes were distributed in fragments. We identified 15 covariate TIFY gene pairs in the loquat genome, 13 of which were involved in large-scale interchromosomal segmental duplication events, and two of which were involved in tandem duplication events. Many abiotic stress cis-elements were widely present in the promoter region. Analysis of the Ka/Ks ratio showed that the paralogous homologs of the EjTIFY family were mainly subjected to purifying selection. Analysis of the RNA-seq data revealed that a total of five differentially expressed genes (DEGs) were expressed in the shoots under gibberellin treatment, whereas only one gene was significantly differentially expressed in the leaves; under both low-temperature and high-temperature stresses, there were significantly differentially expressed genes, and the EjJAZ15 gene was significantly upregulated under both low- and high-temperature stress. RNA-seq and qRT-PCR expression analysis under salt stress conditions revealed that EjJAZ2, EjJAZ4, and EjJAZ9 responded to salt stress in loquat plants, which promoted resistance to salt stress through the JA pathway. The response model of the TIFY genes in the jasmonic acid pathway under salt stress in loquat was systematically summarized.ConclusionsThese results provide a theoretical basis for exploring the characteristics and functions of additional EjTIFY genes in the future. This study also provides a theoretical basis for further research on breeding for salt stress resistance in loquat. RT-qPCR analysis revealed that the expression of one of the three EjTIFY genes increased and the expression of two decreased under salt stress conditions, suggesting that EjTIFY exhibited different expression patterns under salt stress conditions.

Biochemical features of tomato under the influence of gibberellin and its impact on life table and physiology of Tuta absoluta (Merick) (Gelechiidae, Lepidoptera) reared on tomato

The Tomato leaf miner Tuta absoluta is an important agricultural pest and exerts a considerable influence on tomato production across the world. In the present research tomato plants were sprayed with a gibberellin solution at a concentration of 50 µM. The gibberellin treatment resulted in a prolonged duration of T. absoluta preadult stage (33.67 days) compared to control group (27.38 days). The fecundity rate in treated females (82.33 eggs/female) was lowered compared to the controls (96.92 eggs/female). The intrinsic rate of increase (r) (0.080 day−1) was also reduced in treatments compared with the control (0.110 day−1). The finite rate of increase (λ) in treatment (1.084 day−1) decreased compared to the controls (1.116 day−1). The antioxidant system enzymes of T. absoluta, including catalase, peroxidase, and superoxide dismutase (SOD) were increased in treated insects. The gibberellin also increased the activity of detoxifying enzymes including Glutathione s-transferase with two substrates (DCNB and CDNB) and cytochrome P450 compared to the control group. While general esterase did not show significant differences in treatment and control. The secondary metabolites in treated plants including total sugar, total phenol content, anthocyanin, flavonoid and tannin showed an increasing trend. The results clearly show the negative impact of gibberellin on life table and physiology of the tomato leaf miner and can be considered favorable in integrated pest management programs of this pest.

Comparative profile of transcripts from anthers of hybrid plants and parental lines of sunflower

Most heterosis research over the years has focused on increasing vigour and productivity, and less on the multitude of biochemical and molecular phenotypes as an expression of hybrid superiority under favourable or stressful conditions. Plant productivity depends on the microsporogenesis and microgametogenesis processes highly sensitive to unfavorable environmental conditions and other stress factors that often induce the androsterility. The paper presents the results of the expression polymorphism analysis (by RT-qPCR) of candidate genes with functions in DNA replication, recombination, repair, and mitochondrial morpho-functional organization processes in anthers of homozygous and heterozygous sunflower plants with phenotypic differences in male gametophyte (fertile/sterile). A particular interest in this research represented the identification of gene expression patterns in hybrid (F1) plants in norm, for possible associations of transcriptional response with heterozygous effect, and under conditions of induced stress (gibberellin treatment) as a factor in irreversible phenotype change of anthers from fertile to sterile. Thus, the high proportion of different non-additive and transgressive expression patterns in hybrid plants was established, revealing genetic divergence and expression polymorphisms in parental lines. The sterile anther phenotype of hybrid plants obtained by gibberellin treatment of the inflorescence at the buttoning phase is causally related to changes in allelic gene expression patterns at different phases of microsporogenesis.

Characterization of the MIKCC-type MADS-box gene family in blueberry and its possible mechanism for regulating flowering in response to the chilling requirement.

The expression peak of VcAP1.4, VcAP1.6, VcAP3.1, VcAP3.2, VcAG3, VcFLC2, and VcSVP9 coincided with the endo-dormancy release of flower buds. Additionally, GA4+7 not only increased the expression of these genes but also promoted flower bud endo-dormancy release. The MIKCC-type MADS-box gene family is involved in the regulation of flower development. A total of 109 members of the MIKCC-type MADS-box gene family were identified in blueberry. According to the phylogenetic tree, these 109 MIKCC-type MADS-box proteins were divided into 13 subfamilies, which were distributed across 40 Scaffolds. The results of the conserved motif analysis showed that among 20 motifs, motifs 1, 3, and 9 formed the MADS-box structural domain, while motifs 2, 4, and 6 formed the K-box structural domain. The presence of 66 pairs of fragment duplication events in blueberry suggested that gene duplication events contributed to gene expansion and functional differentiation. Additionally, the presence of cis-acting elements revealed that VcFLC2, VcAG3, and VcSVP9 might have significant roles in the endo-dormancy release of flower buds. Meanwhile, under chilling conditions, VcAP3.1 and VcAG7 might facilitate flower bud dormancy release. VcSEP11 might promote flowering following the release of endo-dormancy, while the elevated expression of VcAP1.7 (DAM) could impede the endo-dormancy release of flower buds. The effect of gibberellin (GA4+7) treatment on the expression pattern of MIKCC-type MADS-box genes revealed that VcAP1.4, VcAP1.6, VcAP3.1, VcAG3, and VcFLC2 might promote flower bud endo-dormancy release, while VcAP3.2, VcSEP11, and VcSVP9 might inhibit its endo-dormancy release. These results indicated that VcAP1.4, VcAP1.6, VcAP1.7 (DAM), VcAP3.1, VcAG3, VcAG7, VcFLC2, and VcSVP9 could be selected as key regulatory promoting genes for controlling the endo-dormancy of blueberry flower buds.

The Impact of Magnetic Field and Gibberellin Treatment on the Release of Dormancy and Internal Nutrient Transformation in Tilia miqueliana Maxim. Seeds

The seeds of Tilia miqueliana Maxim. exhibit deep dormancy, which is categorized as combinational dormancy. This study utilized a comprehensive treatment involving magnetic fields, gibberellin (GA3), and cold stratification to promote the release of seed physiological dormancy and enhance germination rates. After being soaked in 98% H2SO4 for 15 min, mature seeds of Tilia were exposed to magnetic field treatments (150 MT, 250 MT) for different durations (25 min, 45 min, 65 min, and 85 min), as well as GA3 solution soaking (concentration: 0 μmol·L−1, 1443 μmol·L−1). Subsequently, cold stratification (0–5 °C) was applied to investigate the effects of these treatments on seed dormancy release and nutrient transformation. The results indicated that the comprehensive treatment involving magnetic field, GA3 solution soaking, and cold stratification effectively released the physiological dormancy of Tilia seeds and improved germination rates. Among the treatments, M150T85G1443 (magnetic field intensity: 150 MT, magnetic field treatment time: 85 min, GA3 soaking concentration: 1433 μmol·L−1) exhibited the most favorable outcome. After 75 days of cold stratification following the comprehensive treatments, the germination rate of M150T85G1443 seeds reached 89%. Additionally, the levels of storage substances such as starches and crude fats within the seeds decreased, while the utilization of soluble sugars and soluble proteins increased. The M150T85G1443 treatment exhibited the highest degree of variation, leading to gradual increases in metabolic activities of the seeds and a transition from dormancy to germination.

Gibberellin promotes cambium reestablishment during secondary vascular tissue regeneration after girdling in an auxin-dependent manner in Populus.

Secondary vascular tissue (SVT) development and regeneration are regulated by phytohormones. In this study, we used an in vitro SVT regeneration system to demonstrate that gibberellin (GA) treatment significantly promotes auxin-induced cambium reestablishment. Altering GA content by overexpressing or knocking down ent-kaurene synthase (KS) affected secondary growth and SVT regeneration in poplar. The poplar DELLA gene GIBBERELLIC ACID INSENSITIVE (PtoGAI) is expressed in a specific pattern during secondary growth and cambium regeneration after girdling. Overexpression of PtoGAI disrupted poplar growth and inhibited cambium regeneration, and the inhibition of cambium regeneration could be partially restored by GA application. Further analysis of the PtaDR5:GUS transgenic plants, the localization of PIN-FORMED 1 (PIN1) and the expression of auxin-related genes found that an additional GA treatment could enhance the auxin response as well as the expression of PIN1, which mediates auxin transport during SVT regeneration. Taken together, these findings suggest that GA promotes cambium regeneration by stimulating auxin signal transduction.

Impact of Plant Growth Regulators on Strawberry Plant – A Review

Strawberry is soft, luscious, nutritious, tasty, and perishable fruit which are grown in temperate climatic conditions where the plant like a small perennial herb and also grown in a sub-tropical climate whose plant behaves as an annual belonging to the family Rosacea. Application of growth regulators has been practiced commercially to increase the production and quality of crops. Gibberellic acid has a significant role in plant heights, number of runners, number of flowers, fruit set percentage, number of fruits, fruit size, fruit weight and fruit quality. In this study we present influence of gibberellic, yield and fruit quality of strawberry, Triacontanol and NAA on growth on yield and quality, chlormequat. Gibberellins are well-known for acting as a long-day hormone in short-day plants. Gibberellin treatment increases vegetative growth but limits flower development applied gibberellic acid promoted blooming and growth. However it was observed that the highest effect on leave, runner, crown, inflorescence and flower production. Triacontanol, Activol and NAA resulted in increased vegetative growth of strawberry as compared control. Highest crown height (7.2cm) was obtained with 100 ppm Activol and highest leaf number/plant (7.2) and leaf region (49.4m2) were obtained with 50ppm tricontanol treated plants.

Development of Mobility Type Upper Limb Power Assist System —Mechanism and Design of Power Assist Device—

In fruit cultivation, viticulture requires the longest working hours in extended arm postures, much of which is carried out in standing postures to accumulate fatigue on arms, shoulders, and legs: a tough working environment. In this study, we propose a power assist system to assist its users in their extended arm work while they move in vineyards. The proposed system largely consists of a mobile robot, a power assist device for work, and a control system. The mobile robot is structured with a tracked vehicle for rough terrain arranged on its left and right sides so that the users can sit between the two vehicles and be assisted by the power assist device for work installed on it. The power assist device for work with a single linear actuator utilizing a linkage mechanism has the function to retain users’ hand attitude angles while assisting the flexion and extension movements of their shoulder, elbow, and carpometacarpal joints. Then, we verify by simulations the effects that the arrangement and lengths of links will have on the carpometacarpal joints’ trajectories as well as on the hand attitude angles. Finally, in order to check the effectiveness of the proposed power assist device for work, we conducted the evaluation experiments for assumed grape-harvesting work and gibberellin treatments. As a result, we proved its work assisting effects from the muscle activity states as well as its applicability to other kinds of work by altering its linkage structure and hand support part.

Vegetative response of shallot (Allium cepa Aggregatum group) bulbs on vernalization and gibberellin treatment in different environments

This research is an initial study of the effects of vernalization and Gibberellins in two different environments. The research was conducted in a split-split plot design with three factors and three times repetition. The main plot was the environment (environment 1, environment 2), the split plot was vernalization temperature (3±2 and 9±2°C), and split-split plot was Gibberellin concentration (0, 50, 100, 150 ppm). The result showed that the vernalizations and Gibberellin have significantly affected plant height (p<0.01). The environment significantly affected plant height, number of tillers, and number of leaves. There was an interaction between Gibberellin and environment treatment on plant height and an interaction between vernalization, Gibberellin, and environment on the number of leaves. The environment with temperature: 29±2.18°C, RH: 45±9.14%, light intensity: 9272±7669 μmol m-2 S-1 showed plant height and the number of tillers higher than other environments, contrary to the number of leaves. According to the principal component analysis, this environment is more suitable for all vernalization and Gibberellin treatments than other environments. The results of this study indicate that the environment more influences vegetative growth than the other two treatments.

Promotion of Growth and Development of ‘Seolhyang’ Strawberry (Fragaria × ananassa Duch.) Runner Plant by Gibberellin Treatment

Promotion of Growth and Development of ‘Seolhyang’ Strawberry (Fragaria × ananassa Duch.) Runner Plant by Gibberellin Treatment

The effect of giving gibberellin at different concentrations on the elongation of palm oil palm oil (borrassus flabelifer)

This research has been carried out in the greenhouse of BAPEDALDA NTT. The method used was an experimental method with a completely randomized design consisting of 4 (four) treatments, namely control (G0), giving gibberellin 100 ppm (G1), gibberellin 200 ppm (G2), and gibberellin 300 ppm (G3), each treatment consisted of 4 (four) replications so that the total experimental unit was 16 units. The parameters of this study were apokol elongation and the percentage of palmyra growth. The data obtained were analyzed using analysis of variance (ANOVA), and continued with the honest significant difference test (BNJ) if there is a difference. The results showed a significant difference between the control and the gibberellin treatment for the apokol length parameter. Meanwhile, the percentage of palm growth showed no effect. The results of the analysis of variance for the average parameter of apokol elongation obtained F-Count &gt; F-Table, where F-Count = 6.67 and F-Table 5% = 3.49. This means that there is an effect of giving gibberellins on the length of the apokol ejection. Because there are differences, it is continued with the Honest Significant Difference (BNJ) test. The results of the BNJ test showed that the G2 treatment was not different from the G1 and G0 treatments and was different from the G3 treatment. The G1 treatment was not different from the G0 treatment but different from the G3 treatment. The G0 treatment was no different from the G3 treatment.

Interaction of VvDELLA2 and VvCEB1 Mediates Expression of Expansion-Related Gene during GA-Induced Enlargement of Grape Fruit.

Exogenous gibberellin treatment can promote early growth of grape fruit, but the underlying regulatory mechanisms are not well understood. Here, we show that VvDELLA2 directly regulates the activity of the VvCEB1 transcription factor, a key regulator in the control of cell expansion in grape fruit. Our results show that VvCEB1 binds directly to the promoters of cell expansion-related genes in grape fruit and acts as a transcriptional activator, while VvDELLA2 blocks VvCEB1 function by binding to its activating structural domain. The exogenous gibberellin treatment relieved this inhibition by promoting the degradation of VvDELLA2 protein, thus, allowing VvCEB1 to transcriptionally activate the expression of cell expansion-related genes. In conclusion, we conclude that exogenous GA3 treatment regulates early fruit expansion by affecting the VvDELLA-VvCEB1 interaction in grape fruit development.

Pengaruh Pemberian Pupuk Kascing dan Hormon Giberellin (Ga3) Terhadap Produksi Benih Mentimun (Cucumis sativus L.)

The need for cucumbers is high but not supported by existing production, so efforts are needed to increase cucumber seed production to meet these needs. This study aims to determine the effect of vermicompost fertilizer and gibberellin hormone in seed production and quality. The research was conducted in Auguts – December 2022 Antirogo, Sumbersari District, Jember Regency. The design used was a factorial Randomized Complete Blok Design (RCBD) with 2 factors and 3 replications. The first factor was vermicompost fertilizer which consisted of 3 levels, namely K1 (240 g/plant), K2 (360 g/plant), and K3 (480 g/plant). The second factor was gibberellin which consisted of 3 levels, namely G1 (100 mg/l), G2 (150 mg/l), and G3(200 mg/l). The data were analyzed using the ANOVA test and continued with the DMRT (Duncan Multiple Range Test) with a level 5%. The result showed that the vermicompost fertilizer treatment hada a significant effect on the K3 level (480 g/plant) on the fruit weight parameter with a value of 556.13 grams and the fruit length parameter of 25.48 cm. The gibberellin treatment showed a very significant effect on the G1 level (100 mg/l) on the flowering age parameter with a value of 23.89. The interaction between the two K2G1 treatments (360 g/plant and 100 mg/l) showed a very significant effect on the parameters of the number of seeds with good planting of 318.02 grains, the weight of seeds with good planting of 5.27 grams,of seed production per hectare of 878.42 kg.

PaLectinL7 enhances salt tolerance of sweet cherry by regulating lignin deposition in connection with PaCAD1.

Lectin receptor-like kinases (LecRLKs), a large family of plant receptor-like kinases, play an important role in plant response to abiotic stresses. However, little information is available about the roles of LecRLKs in the salt stress response of sweet cherry (Prunus avium). Here, an L-type LecRLK gene (PaLectinL7) was characterized from sweet cherry. Subcellular localization analysis revealed that PaLectinL7 is a plasma membrane protein. The expression of PaLectinL7 was up-regulated by salt, drought and exogenously gibberellin treatments. Overexpression of PaLectinL7 in the roots of Gisela 6 enhanced its tolerance to salt stress. Additionally, transcriptome analysis showed that lignin metabolic-related genes were regulated by PaLectinL7 overexpression. Meanwhile, the lignin contents and associated enzymes (CAD and COMT) rose concurrently with PaLectinL7 overexpression under salt stress. We also found that PaCAD1, a key enzyme involved in lignin metabolism, interacted with PaLectinL7 and could be phosphorylated by PaLectinL7 in vitro, suggesting that PaLectinL7 may regulate the enzyme activity of PaCAD1. Therefore, these results indicated that PaLectinL7, as a membrane-bound regulator, promoted lignin deposition by regulating the activities of enzymes related to lignin metabolism, thus enhancing salt tolerance.

Harmonized biochemical modification of cell walls to get permission for entrance of Azospirillum sp. to rice roots

Biological nitrogen-fixation is important in increasing crop efficiency. Azospirillum is a nitrogen-fixing microorganism that naturally coexists with grasses roots. The present study was undertaken to clarify the role of rice root cell walls in the acceptance of two Azospirillum species, alone or in combination with indole-3-acetic acid (IAA) and gibberellic acid (GA3) treatments. Rice seedlings were grown in Yoshida solution for 21 days and then inoculated with A. brasilense and A. irakens in the presence of 0, 0.57, and 1.14 mM of IAA or 0, 0.29, and 0.58 mM GA3 or a combination of 1.14 mM of IAA and 0.58 mM of GA3. The results showed that the amount of hydrogen peroxide, lipid peroxidation, total nitrogen and activity of ferulic acid peroxidase, NADPH oxidase, nitrate reductase, pectin methyl esterase, cellulase, mannanase, xylanase and pectinase were significantly increased in inoculated samples treated with or without phytohormones. The highest activity of these enzymes was observed in A. brasilense- inoculated rice roots in auxin+gibberellin treatment. In the latter, the activity of phenylalanine ammonia lyase and wall ferulic acid peroxidase enzymes, the content of cell wall polysaccharide, lignin, and total phenolic compounds were the least, compared to controls and also with those samples which were inoculated with A. irakens. The results indicate an active role of the wall and its enzymes in allowing bacteria to enter the roots. Understanding this mechanism can improve the methods of inoculating bacteria into plants and increase crop efficiency, which will result in reduced use of chemical fertilizers and their destructive environmental effects.

The intrinsic developmental age signal defines an age-dependent climbing behavior in cucumber

The tendril is a climbing organ in cucurbits and functions in physical support and to avoid shading by neighboring vegetation. However, how cucurbits produce tendrils to obtain climbing ability is largely unknown. In this study, tendril phenotypes were investigated during different developmental stages. Our results revealed that tendril growth exhibited an age-dependent pattern in cucurbits. Tendril growth was inhibited, and the tendril was formed as a short tendril [nonfunctional tendril (nonF-tendril), approximately 0.1 cm] during the seedling stage. In contrast, enhanced cell proliferation and cell expansion led to rapid elongation of the tendril during the climbing stage, and the tendril formed as a functional tendril (F-tendril, approximately 30 cm) to obtain climbing ability. RT-qPCR detection showed that age-dependent tendril growth correlated negatively with the abundance of the conserved age regulator CsmiR156. Defoliation induced CsmiR156 to inhibit CsSPLs, and F-tendril formation and climbing ability were delayed in defoliated cucumbers, which confirmed the role of CsmiR156 in regulating tendril growth in vivo. Additionally, exogenous gibberellin (GA) treatment showed that GA positively regulated tendril growth, and RT-qPCR detection showed that the GA bio-synthetic genes and metabolic genes were affected by age pathway, suggesting that the age pathway depended on GA bio-synthetic and metabolic pathway to regulate cell expansion to determine tendril growth. In summary, our work reveals that change in tendril type is an important marker of phase transition in cucumber, and tendril growth is regulated by an intrinsic developmental age signal, ensuring that the cucumber obtains climbing ability at a suitable age.