Journal of Plant Growth Regulation最新文献

Nano-fertilizers with higher efficacy compared to conventional fertilizers can provide advantage for plant cultivation in both productive and problematic soils. Therefore, this study aimed to determine the effect of nano-calcium (nano-Ca) on lettuce plants grown in saline-boron toxic soil. Nano-calcium fertilizer was prepared from eggshells. Functional and structural properties of nano-Ca was determined by scanning electron microscopy (SEM), x-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR) before plant experiment. The treatments was; control, 40 mM NaCl and 20 mg kg⁻¹ B (NaCl + B), and 40 mM NaCl and 20 mg kg⁻¹ B with 4 mM Nano-Ca (NaCl + B + nano-Ca). The nano-Ca significantly increased the dry weight and calcium (Ca) concentration of lettuce plants under saline-B toxic conditions. Although there was a decrease in the concentrations of sodium (Na), chloride (Cl), and boron (B) with nano-Ca treatment, it was not statistically significant. Salinity and boron toxicity lead to increased lipid peroxidation. In the present study, the production of malondialdehyde (MDA) as a marker for lipid peroxidation, along with a significant decrease in hydrogen peroxide (H₂O₂) concentration, was observed with the application of nano-Ca. There was no significant alteration in superoxide dismutase activity (SOD) observed in lettuce grown under saline and boron toxic conditions. However, catalase activity (CAT) increased with nano-Ca application, while the activity of ascorbate peroxidase (APX) decreased. The study results suggest that nano-Ca serves a protective function for lettuce plants cultivated under saline and boron toxic conditions.

Phytohormones are the key regulators of plant growth, development, and responses to environmental stressors. Among these, jasmonates (JAs) are particularly crucial, derived mainly from α-linolenic acid (α-LA). JAs govern various physiological processes like seed germination, root elongation, and apical hook formation, while also influencing secondary metabolite production and defense mechanisms. Interacting with enzymes, genes, and other growth regulators, JAs modulate intricate signaling pathways, activating metabolic responses in both normal and stressed conditions. Transcription factors such as MYB, WRKY, basic Helix-Loop-Helix (bHLH), and APETALA2/JA-responsive ethylene response factor (AP2/ERF) are central components to JA signaling pathways, impacting the synthesis of bioactive compounds of therapeutic potential. Additionally, JAs act as chemical elicitors, promoting secondary metabolite production in vitro, leveraging advancements in plant cell and tissue culture techniques. In this regard, the present review offers a comprehensive discussion on diverse roles of JAs in plant physiology and biochemistry, including its biosynthesis, and suggests strategies for large-scale bioactive compound production via plant cell and tissue culture methods.

Apple (Malus domestica) is an important economic fruit crop of the temperate regions of world. Apple productivity is known to be affected by several biotic and abiotic stresses. Among these, water scarcity and soil salinity significantly impact the physiological and metabolic processes of apple, leading to economic losses. Apple plants employ intricate physiological responses to combat drought and salt stress which are orchestrated by diverse endogenous molecular regulatory mechanisms. Modern ‘-omics’ analyses have unraveled the roles of various transcription factors in restoring cellular homeostasis and alleviating the adverse effects of drought and salinity stress on apple plants. Important functions of various miRNAs have recently been studied in the post-transcriptional regulation of gene expression under both stresses. Several protein-mediated regulatory networks underlying drought and salt stress adaptation responses in apple have lately been deciphered. All these regulons ultimately induce the biosynthesis and accumulation of protective compounds for mitigating the negative effects of drought and salinity stress on apple growth. This review coherently highlights a bunch of candidate genes involved in regulating drought and salinity stress in apple and is an exemplification of our present understanding of how apple plants respond to these stresses. The functions of these genes can further be carefully exploited for developing apple varieties with anticipated levels of drought and salt stress tolerance.

Drought stress severely restricts crop yields. Changes in root morphology and function are critical to rice performance under drought conditions, affecting water uptake efficiency, hormone regulation, and nutrient absorption. This study explores the responses of two rice lines, IZ036 with a small root system and IZ144 with a large root system, to drought stress (soil water potential of – 30 ± 5 kPa). The results showed that drought stress significantly inhibited the growth and yield of both rice lines by 35.6–58.1%. Under drought stress, the root-to-shoot ratio of IZ144 increased by 17.8–68.0%, while IZ036 decreased by 10.2–59.1%. While IZ036 experienced a significant reduction in leaf water potential under drought stress, no such impact was observed in IZ144. Both varieties exhibited altered tissue anatomy under drought stress, including, reduced leaf vascular size, increased proportion of vascular bundles in root cross-section, and changes in root thickness. Notably, IZ036 displayed cell and vessel shrinkage and leaf deformation. In response to drought stress, both rice lines exhibited elevated concentrations of auxin, salicylic acid and abscisic acid (ABA) in leaves and increased ethylene and gibberellin (GA) in roots. Notably, IZ144 had significantly higher ABA, cytokinin (CTK), GA, and auxin levels in leaves and CTK in roots than IZ036. Overall, our findings highlight the superior drought tolerance of IZ144 over IZ036, as evidenced by enhanced physiological and anatomical performances and more effective hormone distribution in leaves and roots, indicating the importance of root size in determining drought stress resilience in rice.

Pearl millet (Pennisetum glaucum (L.) R. Br.), a vital C4 Panicoid millet crop, predominantly thrives in rainfed regions subject to various abiotic stresses, notably drought and cold stress, limiting its growth potential and yield. As climate change exacerbates water scarcity, understanding methods to mitigate drought's adverse effects becomes crucial. However, particular bacteria flourishing in the rhizosphere, demonstrating resilience to drought and skilled at nurturing plant health, are recognized for their ability to enhance growth under various abiotic stresses. The current study demonstrated the varying effects of Pseudomonas putida MTCC5279 (RA) on mitigating drought stress under low-temperature field conditions for the pearl millet genotypes PRLT2/89–33 (drought-tolerant) and H77/833–2 (drought-resistant). Plants of both genotypes are grown till panicle emergence and subjected to drought stress at the start of January where temperature also drops in field conditions. The compound effect of drought with low temperature severely affects the inflorescence of both the genotypes but RA-inoculated PRLT2/89–33 plants have better performance than their respective control and drought plants as well compared to H77/833–2 genotypes. Abiotic stresses markedly influenced growth metrics, osmolyte buildup, MDA levels, and the capability to scavenge reactive oxygen species (ROS), all of which saw positive modulation following the application of RA in PRLT2/89–33. To our knowledge, this study represents the first comprehensive examination of P. putida-mediated plant growth enhancement in pearl millet under the combined effects of abiotic stresses.

MicroRNAs (miRNAs) are a class of small non-coding RNAs, which play a crucial role in regulating genes involved in plant growth, development, and secondary metabolite production. Capsaicinoids are pepper-specific amides responsible for the pungency in peppers, as well as for the different pharmacological activities of peppers. Comparison of the small RNA libraries generated by deep sequencing of RNA from placental tissue samples of a highly pungent chilli cultivar (Capsicum chinense Jacq. cv. ‘Umorok’) and a non-pungent cultivar (C. annuum cv. ‘Bell pepper’) revealed a total of 69 known miRNAs belonging to 28 families differentially expressed in the placenta of the two pepper cultivars. The GO terms of the majority of the differentially expressed miRNAs are “defense response to other organisms”, “regulation of DNA-templated transcription”, “transport”, “protein metabolic process”, and “phosphorylation”. Many of the target proteins identified in this study, including MYB transcription factors, gibberellin response elements, and transcripts involved in the immune response against fungal pathogens might be involved in regulating capsaicinoids biosynthesis. Significant differential expression of miRNAs targeting conserved genes with known role in regulating capsaicinoids biosynthesis, such as miR162, miR168-3p.1.1, miR166a-5p, miR167-5p, miR6027-3p, miR482a-3p, miR482d-3p.1, and miR6024-3p, indicate their potential involvement in regulating capsaicinoids biosynthesis. These findings thus, identified the differentially expressed miRNAs in C. chinense, which may be selected for future studies to explore the miRNA-mediated mechanism of capsaicinoid accumulation.

The wall-associated kinase (WAK) and WAK-associated kinase-like (WAKL) genes belong to the major receptor-like kinase (RLK) gene family in plants. They are well-known as important candidates for directly transmitting extracellular signals to the cytoplasm by connecting the extracellular matrix with intracellular compartments. As a result, they participate in developmental processes as well as stress responses. Although genome-wide investigations of the WAK/WAKL gene family have been carried out in a number of plant species, little is known about the WAK/WAKL genes in sugar beet, Beta vulgaris subsp. vulgaris L. (BvWAK/WAKLs). In this study, we performed a computational large-scale characterization of the members of this gene family in sugar beet. Fifty five (55) sugar beet WAK/WAKL proteins exhibited a wide range of physicochemical properties. A total of 10 conserved motifs were identified from all BvWAK/WAKL proteins, of which 3 motifs could be used as specific motif markers for distinguishing BvWAKs from BvWAKLs. Gene structure analysis showed that most BvWAK/WAKL genes contained 3 or 4 exons with no obvious phylogenetic organization. Among BvWAK/WAKL genes, 50 were assigned to their chromosomal locations and shown to have expanded primarily through tandem duplication. Comparative phylogeny revealed that sugar beet WAK/WAKL genes were divided into six clades, and orthologous gene pairs were identified between sugar beet and its wild-related species, the sea beet (Beta vulgaris subsp. maritima L.), while B. maritima lineage-specific genes provided clues for the introduction of wild genes in sugar beet cultivars. The gene expression data analysis revealed that the BvWAK/WAKL genes of susceptible and resistant cultivars were differentially expressed in response to beet cyst nematode (BCN) infection, and that 13 BvWAK/WAKL genes were up-regulated only in the resistant cultivar, suggesting that they are potentially involved in the resistance of sugar beet against this nematode. For the first time in sugar beet, our study presents an extensive computation-based knowledge platform on WAK/WAKL gene family and provides candidate genes for deeper molecular investigation of their potential role in sugar cyst nematode resistance.

Phosphate-solubilizing bacteria (PSB) are well known to enhance P availability and crop yield. However, profound understanding of crop responses to inoculation under contrasting conditions and throughout crop growth stages are so far incomplete. That is the case when employing bacterial consortia, which involve intricate species interactions likely ensuring complementary functions for a better plant growth and nutrient acquisition. This study, therefore, aimed to evaluate agro-physiological responses of durum wheat (under different growth stages) to the combined application of three PSB consortia (BC_a, BC_b, and BC_c) and rock P (RP) versus three uninoculated control treatments (unfertilized “P₀”, fertilized with RP and orthophosphate “OrthoP”) under controlled and field conditions. Overall, BC inoculation significantly enhanced grain yield, nutrient uptake, and physiological performance under both controlled and field conditions, and at a comparable level to OrthoP application. Particularly, BC_c significantly enhanced biomass and number of spikes under field conditions yielding 2-times higher grain yield than uninoculated RP treatment. This improvement can be attributed to enhanced biomass of shoots (40.6 and 102.1%) and roots (37.3 and 156.5%) under both conditions compared to uninoculated RP-fertilized plants. Spikes nutrient content also increased significantly (P “81%”, N “72%”, and K “71%”) along with grain yield (average of 68.3%) in response to BC (mainly BC_c), which can be attributed to the capacity of BC to enhance rhizosphere available P through induced acid phosphatases activity and growth traits of roots. However, across plant growth stages (30-, 75-, and 95-day old) there was a noticed decrease in rhizosphere available P (51.5, 47.6 and 25.3%) concomitantly to increased soil microbial biomass P (60.3, 107.8, and 86.7%) compared to uninoculated RP-fertilized plants. The increase of both soil microbial biomass P and wheat agro-physiological performance can be directly attributed to positive impacts of BC across different stages of plant growth, demonstration a significant ecological contribution to sustain wheat production under low P conditions.

It is not known whether both reducing tiller-fertilizer and increasing panicle-fertilizer can significantly increase grain yield under mechanical deep placement. The two-year field experiment was conducted to access the effects of optimal nitrogen fertilization including reducing tiller-fertilizer, increasing panicle-fertilizer, with the method of mechanical deep placement on grain yield and its physiological traits of rice, in 2019 and 2020. The experimental materials were selected with hybrid rice Wufengyou615 (WFY615) and inbred rice Yuxiangyouzhan (YXYZ). There were six experiment treatments, i.e., no any fertilization (H1); traditional surface broadcast fertilization (SB) (90 kg N ha⁻¹ as basal fertilization (BF) and 60 kg N ha⁻¹ as tillering fertilizer (TF), namely, BF 90 kg N (SB) + TF 60 kg N (SB), (H2); BF 90 kg N (SB) + TF 45 kg N (DP, deep placement) + FF (flowering fertilizer) 7.5 kg N (SB), (H3); BF 90 kg (SB) + TF 45 kg N (DF) + FF 15 kg N (SB), (H4); BF 90 kg N(SB) + TF 30 kg N (DP) + FF 7.5 kg N (SB), (H5); BF 90 kg N (SB) + TF 30 kg N (DP) + FF 15 kg N (SB), (H6). The results showed that mean grain yield of WFY615 and YXYZ for H4 was 10.57 t ha⁻¹ and 10.42 t ha⁻¹, which was 14.58% and 7.49% higher than H2, respectively. The main reason was due to the increase of productive panicle per ha, spikelet per panicle and grain filling percentage. The highest total dry matter of WFY615 and YXYZ at heading (HS) and mature stages (MS) was for H4, which was 9.24, 15.97, 11.65, and 14.71 t ha⁻¹, respectively. There was 31.09, 25.96, 41.73, and 20.58% higher total dry matter material of WFY615 and YXYZ for H4 than H2 at HS and MS, respectively. The largest leaf area index of H4 was also found at HS and fifteen days after HS for two rice cultivars, which was 6.24, 8.79, 6.09, and 8.29, respectively. The H4 treatment had the largest net photosynthetic rate, followed by H3 and H2, while the least net photosynthetic rate was recorded for H1. In addition, significant improvements were also founded in chlorophyll content, glutamate synthase, and nitrate reductase activities of sword leaves at HS for H4. Therefore, the fertilizer management can be regarded as one of high-efficiency fertilization method with 90 kg N ha⁻¹ basal fertilizer by surface broadcast plus 45 kg N ha⁻¹ tillering fertilizer under mechanical deep placement and 15 kg N ha⁻¹ flowering fertilizer by surface broadcast.

Cotton is the major natural fiber-producing crop, contributing significantly to the global textile economy. However, the cotton crop encounters several biotic and abiotic stress challenges globally, causing substantial annual yield loss. Plant responses to such diverse stress conditions involve intricate molecular and physiological modifications at the cellular level. Here, we employed a genomics approach to illustrate comprehensive spatial transcriptomic profiles in response to various insect infestations, including aphids (Aphis gossypii), cotton boll weevils (Anthonomus grandis), cotton bollworms (Helicoverpa armigera), whiteflies (Bemisia tabaci), and drought stress. Comparative temporal expression analysis with a strict log-fold change threshold (> 2.0) revealed distinct gene expression patterns in different tissues of cotton plants, with selected pivotal ‘stress-general’ and ‘stress-specific’ genes involved in plant defense mechanisms against various infestations and drought conditions. The expression of at least 5 insect-general transcription factor-encoding genes, WRKY28, WRKY40, WRKY53, ERF4, and ERF5, was highly upregulated across cotton leaf tissues infested by aphids, cotton bollworms, and whiteflies. Additionally, a set of highly upregulated ‘stress-specific’ genes, including GH3.1, ACS1, CYP74A, TIFY10A, BHLH25, ABR1, and ERF025, were identified especially after a 6-h period of cotton bollworm infestation. Similarly, various sets of such ‘stress-specific’ spatially upregulated genes were identified across diverse insect infestations. Functional annotation of differentially expressed genes revealed the upregulation of various defense-related functions such as stress hormone signal transduction, MAPK signaling pathway, and biosynthesis of secondary metabolites, orchestrating the plant’s defense mechanisms. Further, spatiotemporal expression analysis of ‘stress-general’ genes in response to abiotic stresses revealed that GhWRKY28 was highly upregulated in response to both biotic and abiotic stress conditions. The findings suggested that the identified ‘stress-general’ genes could serve as suitable candidates for manipulating crops for multiple stress resistance/tolerance.