Parthenocarpy is an important way for seedless fruit production in citrus. However, the molecular mechanism(s) of parthenocarpy in pomelo is still unknown. Our initial study found significantly different parthenocarpic abilities in Guanximiyou (G) and Shatianyou (S) pomelo following emasculation, and an endogenous hormone content assay revealed that indole-3-acetic acid (IAA), gibberellic acid (GA3) and zeatin (ZT) jointly promoted fruit expansion and cell division in parthenocarpic pomelo (G pomelo). To unravel the underlying molecular mechanism(s), we conducted the first transcriptome analysis on the two pomelo accessions at these two critical stages: the fruit initiation stage and the rapid expansion stage, in order to identify genes associated with parthenocarpy. This analysis yielded approximately 7.86 Gb of high-quality reads, and the subsequent de novo assembly resulted in the identification of 5,792 DEGs (Differentially Expressed Genes). Among these, a range of transcription factor families such as CgERF, CgC2H2, CgbHLH, CgNAC and CgMYB, along with genes like CgLAX2, CgGH3.6 and CgGH3, emerged as potential candidates contributing to pomelo parthenocarpy, as confirmed by qRT-PCR analysis. The present study provides comprehensive transcriptomic profiles of both parthenocarpic and non-parthenocarpic pomelos, reveals several metabolic pathways linked to parthenocarpy, and highlights the significant role of plant hormones in its regulation. These findings deepen our understanding of the molecular mechanisms underlying parthenocarpy in pomelo.

To investigate the synergistic effect of IAA and melatonin (MT) on three plants to alleviate the effects of salt damage on plants, we aim to determine the optimal concentrations of exogenous hormone treatments that improve salinity resistance for each species. In this experiment, three desert plants, Sarcozygium xanthoxylon, Nitraria tangutorum, and Ammopiptanthus mongolicus, which are common in Wuhai City, were used as plant materials. Two time periods (12 h,24 h) of exogenous hormone IAA (100 μmol/L) and exogenous melatonin concentration (0, 100, 200, 300 μmol/L) were used to treat the three desert plants in saline soil under different conditions of exogenous IAA and exogenous melatonin. The results indicate that under different concentrations of exogenous IAA and melatonin, the germination rate and vigor of the three desert plant species in saline-alkaline soil improved. However, as the concentration of melatonin increased, the germination rate and vigor of these desert plants were inhibited. Whereas, plant height, root length, leaf length, fresh weight, dry weight, and root vigor of the three desert plants were alleviated under different conditions of exogenous IAA and exogenous melatonin. under the action of two exogenous hormones, the low concentration of melatonin decreased their malondialdehyde content and increased their proline content. As melatonin levels increased, the activity of antioxidant enzymes also rose initially, followed by a subsequent decline. This study highlights the synergistic effects of two exogenous hormones on the critical role of cell osmomodulators and antioxidant enzyme activity in combating salinity damage in three desert plants.

Waterlogging stress causes substantial destruction to plant growth and production under climatic fluctuations globally. Plants hormones have been widely explored in numerous crops, displaying an imperative role in crop defense and growth mechanism. However, there is a paucity of research on the subject of plant hormones regulating waterlogging stress responses in wheat crop. In this study, we clarified the role of 6-BA in waterlogging stress through inducing phenylpropanoid biosynthesis in wheat. The application of 6-BA (6-benzyladenine) enhanced the growth and development of wheat plants under waterlogging stress, which was accompanied by reduced electrolyte leakage, high chlorophyll, and soluble sugar content. ROS scavenging was also enhanced by 6-BA, resulting in reduced MDA and H2O2 accumulation and amplified antioxidant enzyme activities. Additionally, under the effect of 6-BA, the acceleration of lignin content and accumulation in the cell walls of wheat tissues, along with the activation of PAL (phenylalanine ammonia lyase), TAL (tyrosine ammonia lyase), and 4CL (4-hydroxycinnamate CoA ligase) activities and the increase in the level of transcription of the TaPAL and Ta4CL genes, were observed under waterlogging stress. Also, 6-BA improved the root growth system under waterlogging stress conditions. Further qPCR analysis revealed increased auxin signaling (TaPR1) in 6-BA-treated plants under waterlogging stress that was consistent with the induction of endogenous IAA hormone content under waterlogging stress conditions. Here, 6-BA also reduced yield loss, as compared to control plants. Thus, the obtained data suggested that, under the application of 6-BA, phenylpropanoid metabolism (i.e., lignin) was stimulated, playing a significant role in reducing the negative effects of waterlogging stress on yield, as evinced by the improved plant growth parameters.

Abiotic stresses, especially drought stress and salt stress in crop plants are accelerating due to climate change. The combined impact of drought and salt is anticipated to lead to the loss of up to 50% of arable land globally, resulting in diminished growth and substantial yield losses threatening food security. Addressing the challenges, agriculture through sustainable practices emerges as a potential solution to achieve Zero Hunger, one of the sustainable development goals set by the IUCN. Plants deploy a myriad of mechanisms to effectively address drought and salt stress with phytohormones playing pivotal roles as crucial signaling molecules for stress tolerance. The phytohormone auxin, particularly indole acetic acid (IAA) emerges as a paramount regulator integral to numerous aspects of plant growth and development. During both drought and salt stress conditions, auxin plays crucial roles for tolerance, but stress-induced processes lead to decreased levels of endogenous free auxin in the plant, leading to an urgent need for auxin production. With an aim to augment this auxin deficiency, several researchers have extensively investigated auxin production, particularly IAA by plant-associated microorganisms, including endophytic bacteria. These endophytic bacteria have been introduced into various crop plants subjected to drought or salt stress and potential isolates promoting plant growth have been identified. However, post-identification, essential studies on translational research to advance these potential isolates from the laboratory to the field are lacking. This review aims to offer an overview of stress tolerant auxin-producing endophytic bacterial isolates while identifying research gaps that need to be fulfilled to utilize this knowledge for the formulation of crop-specific and stress-specific endophyte bioinoculants for the plant to cope with auxin imbalance occurring during these stress conditions.

Thiol-disulfide interconversions are pivotal in the intricate chemistry of biological systems. They play a vital role in governing cellular redox potential and shielding against oxidative harm. These interconversions can also act as molecular switches within an expanding array of redox-regulated proteins, facilitating dynamic and responsive processes. Furthermore, metal-binding proteins often use thiols for coordination. Reverse thiol trapping is a valuable analytical tool to study the redox state of cysteines in biological systems. By selectively capturing and stabilizing free thiol species with an alkylating agent, reverse thiol trapping allows for their subsequent identification and quantification. Various methods can be employed to analyze the trapped thiol adducts, including electrophoresis-based methods, mass spectrometry, nuclear magnetic resonance spectroscopy, and chromatographic techniques. In this chapter, we will focus on describing a simple and sensitive method to sequentially block thiols in their cellular state with a cell-permeant agent (iodoacetamide), and following reduction and denaturation of the samples, trap the native disulfides with a second blocker that shifts the apparent molecular weight of the protein. The oxidation status of proteins for which suitable antibodies are available can then be analyzed by immunoblotting. We present examples of mitochondrial proteins that use cysteine thiols to coordinate metal factors such as iron-sulfur clusters, zinc, and copper.

Axillary bud is an important aspect of plant morphology, contributing to the final tobacco yield. However, the mechanisms of axillary bud development in tobacco remain largely unknown. To investigate this aspect of tobacco biology, the metabolome and proteome of the axillary buds before and after topping were compared. A total of 569 metabolites were differentially abundant before and 1, 3, and 5 days after topping. KEGG analyses further revealed that the axillary bud was characterized by a striking enrichment of metabolites involved in flavonoid metabolism, suggesting a strong flavonoid biosynthesis activity in the tobacco axillary bud after topping. Additionally, 9035 differentially expressed proteins (DEPs) were identified before and 1, 3, and 5 days after topping. Subsequent GO and KEGG analyses revealed that the DEPs in the axillary bud were enriched in oxidative stress, hormone signal transduction, MAPK signaling pathway, and starch and sucrose metabolism. The integrated proteome and metabolome analysis revealed that the indole-3-acetic acid (IAA) alteration in buds control dormancy release and sustained growth of axillary bud by regulating proteins involved in carbohydrate metabolism, amino acid metabolism, and lipid metabolism. Notably, the proteins related to reactive oxygen species (ROS) scavenging and flavonoid biosynthesis were strongly negatively correlated with IAA content. These findings shed light on a critical role of IAA alteration in regulating axillary bud outgrowth, and implied a potential crosstalk among IAA alteration, ROS homeostasis, and flavonoid biosynthesis in tobacco axillary bud under topping stress, which could improve our understanding of the IAA alteration in axillary bud as an important regulator of axillary bud development.

UNASSIGNED: The Salkowski reagent method is a colorimetric technique used to determine auxin production, specifically as indole-3-acetic acid (IAA). It was developed to determine indoles rapidly; however, it does not follow Beer\'s law at high concentrations of IAA. Thus, there could be an overestimation of IAA with the Salkowski technique due to the detection of other indole compounds.
UNASSIGNED: This study aims to compare the Salkowski colorimetric method versus a chromatographic method to evidence the imprecision or overestimation obtained when auxins, such as indole-acetic acid (IAA), are determined as traits from promoting growth plant bacteria (PGPB), using ten different strains from three different isolation sources. The analysis used the same bacterial culture to compare the Salkowski colorimetric and chromatographic results. Each bacterium was cultivated in the modified TSA without or with tryptophan for 96 h. The same supernatant culture was used in both methods: Salkowski reagent and ultra-performance liquid chromatography coupled with a Mass Spectrometer (LC-MS/MS).
UNASSIGNED: The first method indicated 5.4 to 27.4 mg L-1 without tryptophan in ten evaluated strains. When tryptophan was used as an inductor of auxin production, an increase was observed with an interval from 4.4 to 160 mg L-1. The principal auxin produced by all strains was IAA from that evaluated by the LC-MS/MS method, with significantly higher concentration with tryptophan addition than without. Strains belonging to the Kocuria genus were highlighted by high IAA production. The indole-3-propionic acid (IPA) was detected in all the bacterial cultures without tryptophan and only in K. turfanensis As05 with tryptophan, while it was not detected in other strains. In addition, indole-3-butyric acid (IBA) was detected at trace levels (13-16 µg L-1).
UNASSIGNED: The Salkowski reagent overestimates the IAA concentration with an interval of 41-1042 folds without tryptophan and 7-16330 folds with tryptophan as inductor. In future works, it will be necessary to determine IAA or other auxins using more suitable sensitive techniques and methodologies.

Small auxin-upregulated RNAs (SAURs), as the largest family of early auxin-responsive genes, play important roles in plant growth and development processes, such as auxin signaling and transport, hypocotyl development, and tolerance to environmental stresses. However, the functions of few SAUR genes are known in the root development of sweet potatoes. In this study, an IbSAUR36 gene was cloned and functionally analyzed. The IbSAUR36 protein was localized to the nucleus and plasma membrane. The transcriptional level of this gene was significantly higher in the pencil root and leaf.This gene was strongly induced by indole-3-acetic acid (IAA), but it was downregulated under methyl-jasmonate(MeJA) treatment. The promoter of IbSAUR36 contained the core cis-elements for phytohormone responsiveness. Promoter β-glucuronidase (GUS) analysis in Arabidopsis showed that IbSAUR36 is highly expressed in the young tissues of plants, such as young leaves, roots, and buds. IbSAUR36-overexpressing sweet potato roots were obtained by an efficient Agrobacterium rhizogenes-mediated root transgenic system. We demonstrated that overexpression of IbSAUR36 promoted the accumulation of IAA, upregulated the genes encoding IAA synthesis and its signaling pathways, and downregulated the genes encoding lignin synthesis and JA signaling pathways. Taken together, these results show that IbSAUR36 plays an important role in adventitious root (AR) development by regulating IAA signaling, lignin synthesis, and JA signaling pathways in transgenic sweet potatoes.

Nymphoides coronata is an endangered aquatic plant species with significant medicinal and ecological importance. To preserve N. coronata from going extinct, we need to provide seedlings and efficient multiplication techniques so that it can be extensively studied. This study aimed to identify the most suitable sterilization treatment, growth medium, and substrate for the cultivation and propagation of N. coronata. Ethanol sterilization, fungicide treatment, and sterile water washing were the most important sterilization steps. A combination of 6-benzylaminopurine (6-BA) and indoleacetic acid (IAA) was the most suitable medium for bud induction and shoot proliferation. The use of α-naphthaleneacetic acid (NAA) increased the rooting rate and rooting time compared to indole-3-butyric acid (IBA). Increasing the concentration of NAA from 0.5 to 1.0 mg/L increased the rooting rate from 78 to 100% and reduced the rooting time from 7 to 5 days. The survival rate of N. coronata seedlings was 100% in a mixture of red soil and sand (1:1, w/w). As a result, the procedure mentioned above could potentially be used to safely propagate this rare species on a large scale. These findings provide valuable insights into the optimal conditions for the successful cultivation and propagation of N. coronata, which can contribute to the conservation and sustainable use of this important rare plant species.

Lesions of the semilunar valve and the aortic arch can occur either in isolation or as part of well-described clinical syndromes. The polygenic cause of calcific aortic valve disease will be discussed including the key role of NOTCH1 mutations. In addition, the complex trait of bicuspid aortic valve disease will be outlined, both in sporadic/familial cases and in the context of associated syndromes, such as Alagille, Williams, and Kabuki syndromes. Aortic arch abnormalities particularly coarctation of the aorta and interrupted aortic arch, including their association with syndromes such as Turner and 22q11 deletion, respectively, are also discussed. Finally, the genetic basis of congenital pulmonary valve stenosis is summarized, with particular note to Ras-/mitogen-activated protein kinase (Ras/MAPK) pathway syndromes and other less common associations, such as Holt-Oram syndrome.