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Glucosinolates (GLS) contribute to the unique flavour, nutrition, and plant defence of the Cruciferous vegetables. Understanding the GLS changes through postharvest processing is essential for defined preservation. In this study, four different fresh-cut types, whole flower (W), floret (F), quarterly cut floret (QF) and shredded floret (FS) of broccoli, were stored for 0, 1, 2 and 3 day (s) to explore GLS responses to postharvest treatments. As a result, seven GLS were identified, mainly including glucoraphanin (RAA), neoglucobrassicin (NEO), and glucobrassicin (GBC) and accounting for 52.69%, 20.12% and 14.99% of the total GLS (21.92 ± 0.48) μmol · g-1DW, respectively. FS had the sharpest decrease in GLS after three days of storage (6.55 ± 0.37) μmol · g-1DW, while QF had the least (10.16 ± 0.33) μmol · g-1DW. All GLS components decreased over storage, except for 4-methoxyglucobrassicin (4 ME) in FS and QF, suggesting its key role in serious wound defence. The results suggested certain postharvest approaches influenced the flavour and nutrition of broccoli.

Regeneration serves as a self-protective mechanism that allows a tissue or organ to recover its entire form and function after suffering damage. However, the regenerative capacity varies greatly within the plant kingdom. Primitive plants frequently display an amazing regenerative ability as they have developed a complex system and strategy for long-term survival under extreme stress conditions. The regenerative ability of dicot species is highly variable, but that of monocots often exhibits extreme recalcitrance to tissue replenishment. Recent studies have revealed key factors and signals that affect cell fate during plant regeneration, some of which are conserved among the plant lineage. Among these, several members of the ETHYLENE RESPONSE FACTOR (ERF) transcription factors have been implicated in wound signaling, playing crucial roles in the regenerative mechanisms after different types of wounding. An understanding of plant regeneration may ultimately lead to an increased regenerative potential of recalcitrant species, producing more high-yielding, multi-resistant and environmentally friendly crops and ensuring the long-term development of global agriculture.

Wounding triggers organ regeneration in many plant species, and application of plant hormones, such as auxin and cytokinin, enhances their regenerative capacities in tissue culture. Recent studies have identified several key players mediating wound- and/or plant hormone-induced cellular reprogramming, but the global architecture of gene regulatory relationships underlying plant cellular reprogramming is still far from clear. In this study, we uncovered a gene regulatory network (GRN) associated with plant cellular reprogramming by using an enhanced yeast one-hybrid (eY1H) screen systematically to identify regulatory relationships between 252 transcription factors (TFs) and 48 promoters. Our network analyses suggest that wound- and/or hormone-invoked signals exhibit extensive cross-talk and regulate many common reprogramming-associated genes via multilayered regulatory cascades. Our data suggest that PLETHORA 3 (PLT3), ENHANCER OF SHOOT REGENERATION 1 (ESR1) and HEAT SHOCK FACTOR B 1 (HSFB1) act as critical nodes that have many overlapping targets and potentially connect upstream stimuli to downstream developmental decisions. Interestingly, a set of wound-inducible APETALA 2/ETHYLENE RESPONSE FACTORs (AP2/ERFs) appear to regulate these key genes, which, in turn, form feed-forward cascades that control downstream targets associated with callus formation and organ regeneration. In addition, we found another regulatory pathway, mediated by LATERAL ORGAN BOUNDARY/ASYMMETRIC LEAVES 2 (LOB/AS2) TFs, which probably plays a distinct but partially overlapping role alongside the AP2/ERFs in the putative gene regulatory cascades. Taken together, our findings provide the first global picture of the GRN governing plant cell reprogramming, which will serve as a valuable resource for future studies.

Plants reprogram somatic cells following injury and regenerate new tissues and organs. Upon perception of inductive cues, somatic cells often dedifferentiate, proliferate, and acquire new fates to repair damaged tissues or develop new organs from wound sites. Wound stress activates transcriptional cascades to promote cell fate reprogramming and initiate new developmental programs. Wounding also modulates endogenous hormonal responses by triggering their biosynthesis and/or directional transport. Auxin and cytokinin play pivotal roles in determining cell fates in regenerating tissues and organs. Exogenous application of these plant hormones enhances regenerative responses in vitro by facilitating the activation of specific developmental programs. Many reprogramming regulators are epigenetically silenced during normal development but are activated by wound stress and/or hormonal cues. [ABSTRACT FROM AUTHOR]

Eggplant is an agronomically important non-tuberous commercial crop belongs to Solanaceae family grown primarily for its large oval fruit. Herein, we have formulated an efficient in planta transformation method for brinjal by employing thiol compounds as antioxidants to eradicate wound stress. The seeds were initially infected with Agrobacterium tumefaciens EHA 105 harbouring pCAMBIA1301 plasmid and co-cultivated with different concentrations and combinations of antioxidants. The thiol compounds used in the present study were L-cysteine, Sodium thiosulfate and dithiothreitol. After cocultivation, the transformed seedlings were selected with 4.0 mg l-1 Hygromycin B. The survived seedlings were analysed by GUS and PCR assay for the presence of transformed genes. The integration of transgene in the plant genome was also confirmed by Southern blot hybridization. Among the different concentrations and combinations tested, collective supplementation of 400 mg l-1 L-cysteine, 250 mg l-1 STS and 150 mg l-1 DTT enhanced the viability of seedlings by reducing primary and secondary responses of injured plants. With the aid of thiol compounds, the formulated protocol attained the highest transformation efficiency of 53% in brinjal cv. Pusa Kranti. [ABSTRACT FROM AUTHOR]

Regeneration serves as a self-protective mechanism that allows a tissue or organ to recover its entire form and function after suffering damage. However, the regenerative capacity varies greatly within the plant kingdom. Primitive plants frequently display an amazing regenerative ability as they have developed a complex system and strategy for long-term survival under extreme stress conditions. The regenerative ability of dicot species is highly variable, but that of monocots often exhibits extreme recalcitrance to tissue replenishment. Recent studies have revealed key factors and signals that affect cell fate during plant regeneration, some of which are conserved among the plant lineage. Among these, several members of the ETHYLENE RESPONSE FACTOR (ERF) transcription factors have been implicated in wound signaling, playing crucial roles in the regenerative mechanisms after different types of wounding. An understanding of plant regeneration may ultimately lead to an increased regenerative potential of recalcitrant species, producing more high-yielding, multi-resistant and environmentally friendly crops and ensuring the long-term development of global agriculture. [ABSTRACT FROM AUTHOR]

Tissue wounds are mainly caused by herbivory, which is a serious threat for macro-algae, and brown algae are known to regenerate branches or buds in response to wounding. In the present paper, we describe a branch regeneration system, induced by sever damage, in the brown alga Dictyota dichotoma. Segmentations of juvenile thalli induced branch regenerations unless explants possessed apical cells. Apical excisions in distinct positions elucidated that disruption of an apical cell or disconnection of tissue with an apical cell triggered the branch regeneration. Furthermore, spatial positions of regenerated branches seemed to be regulated by the apical region, which was assumed to generate inhibitory effects for lateral branch regeneration. Mechanical incision, which disrupted tissue continuity with the apical region, induced branch regeneration preferentially below the incision. Although we were unable to identify the candidate inhibitory substance, our results suggested that the apical region may have an inhibitory effect on lateral branch regeneration. Additionally, observations of branch regeneration showed that all epidermal cells in D. dichotoma possess the ability to differentiate into apical cells, directly. This may be the first report of algal transdifferentiation during the wound-stress response. [ABSTRACT FROM AUTHOR]

Jasmonate (JA) and auxin are essential hormones in plant development and stress responses. While the two govern distinct physiological processes, their signaling pathways interact at various levels. Recently, members of the Arabidopsis indole-3-acetic acid (IAA) amidohydrolase (IAH) family were reported to metabolize jasmonoyl-isoleucine (JA-Ile), a bioactive form of JA. Here, we characterized three IAH members, ILR1, ILL6, and IAR3, for their function in JA and IAA metabolism and signaling. Expression of all three genes in leaves was up-regulated by wounding or JA, but not by IAA. Purified recombinant proteins showed overlapping but distinct substrate specificities for diverse amino acid conjugates of JA and IAA. Perturbed patterns of the endogenous JA profile in plants overexpressing or knocked-out for the three genes were consistent with ILL6 and IAR3, but not ILR1, being the JA amidohydrolases. Increased turnover of JA-Ile in the ILL6- and IAR3-overexpressing plants created symptoms of JA deficiency whereas increased free IAA by overexpression of ILR1 and IAR3 made plants hypersensitive to exogenous IAA conjugates. Surprisingly, ILL6 overexpression rendered plants highly resistant to exogenous IAA conjugates, indicating its interference with IAA conjugate hydrolysis. Fluorescent protein-tagged IAR3 and ILL6 co-localized with the endoplasmic reticulum-localized JA-Ile 12-hydroxylase, CYP94B3. Together, these results demonstrate that in wounded leaves JA-inducible amidohydrolases contribute to regulate active IAA and JA-Ile levels, promoting auxin signaling while attenuating JA signaling. This mechanism represents an example of a metabolic-level crosstalk between the auxin and JA signaling pathways. [ABSTRACT FROM AUTHOR]

Grafting is a technology widely used in agriculture and biological research. During a hetero-grafting process, cutting wound and hetero-grafting per se are the two main stimuli invoking cellular and whole-plant responses. Despite the importance of dissecting the individual effects of the two in adequately interpreting experimental data, no currently published data are dedicated to comparing the effects of hetero-grafting per se and grafting wound. In this study, isobaric tags for relative and absolute quantitation (iTRAQ) technique-based proteomic analyses were conducted between various scion-rootstock combinations of bottle gourd. Our results demonstrated that effects of grafting wound and hetero-grafting per se were readily distinguishable at the proteome level. Grafting wound affected the proteomes differentially at the graft union and its upper vicinity. Its effects were also likely related to the stress resistance level of each genotype. The effects of hetero-grafting per se on proteome were markedly different between graft union and the upper vicinity. This study provides an explicit evidence for the effectiveness of the commonly used methods of eliminating the effects of grafting wound in a hetero-grafting system by setting up a homo-grafted control. The role of hydrogen peroxide as a signal molecule in hetero-grafting systems is suggested. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) easily diffuse due to their high hydrophobicity. Because of this physical property, VOCs are able to act as crucial signalling molecules mediating intercellular and interplant communication. Methyl jasmonate (MeJA) is a volatile ester form of jasmonic acid (JA) that is involved in interplant communication in response to biotic and abiotic stresses. Despite its function in interplant communication, the specific role of MeJA in the regulation of intercellular jasmonate responses have been poorly understood. In this study, we demonstrated that MeJA is much more effective than JA in inducing jasmonate response, and the higher efficacy of MeJA relies on its volatile property. To understand the function of MeJA in the regulation of the jasmonate response, we analysed function of JMT gene, Jasmonic acid Methyl Transferase using its knockout mutant ( jmt) and overexpressing plants ( 35S:JMT). Mutant plants that lack JMT expression exhibited reduced jasmonate response, while JMT-overexpressing plants exhibited a higher jasmonate response to JA treatment compared to wild-type plants. In this study, we also showed that JMT is specifically expressed in the phloem, the main vascular system for the transport of phytohormones, and that JMT expression affects systemic jasmonate response in wounding. These results suggest the volatile MeJA is a transmissible form of jasmonate and that its biosynthesis is involved in systemic jasmonate response in wounding. [ABSTRACT FROM AUTHOR]

The seed coat serves as a multifunctional organ with a role in protection and for the supply of nutrients to the embryo sac during development. The composition of the legume seed coat differs from other seed tissues in many ways including its protein composition. An abundant 24 kDa protein (SC24) has been purified and identified from soybean (Glycine max [L.] Merr) seed hulls. The corresponding cDNA and genomic DNA clones for SC24 were isolated and characterized, and expression patterns were determined. The deduced protein sequence of 219 amino acids included an N-terminal signal peptide. Transcripts encoding SC24 were present in the seed coat from 30 days after pollination (DAP) until maturity, but the protein was not detected until the final stages of seed maturation. In mature seeds, most of the SC24 protein was localized to the parenchyma and aleurone layers of the seed coat. The expression of SC24 was also induced in vegetative tissues by pathogen infection and by wounding. The SC24 protein bound to an affinity column containing an isophthalic acid ligand, and was eluted with 7 mM citrate. Polyclonal antibodies raised against recombinant SC24 cross-reacted with the seed coat peroxidase enzyme, suggesting that these two proteins may share an antigenic determinant. Overall, the results indicate that SC24 belongs to a novel class of plant defence proteins with carboxylate-binding activity. [ABSTRACT FROM PUBLISHER]

Superoxide dismutase, peroxidase and catalase are major antioxidative enzymes that contribute to the oxidative stress response in plants. The activity of these enzymes was measured in wound-stressed rice plants that were wounded at seedling stage, maximum tillering stage or flowering stage. Kinetics of enzyme activity were examined in leaf extracts post-wounding. Superoxide dismutase activity increased rapidly until 6 h after wounding and was maintained at a high level throughout development. Wound stress-induced changes in manganese superoxide dismutase and copper–zinc superoxide dismutase activities were detected using a native activity gel. In contrast, catalase was rapidly deactivated and peroxidase was transiently activated and then deactivated after wounding. However, high peroxidase activity was maintained at maximum tillering stage of development. These observations suggest that rice antioxidant enzymes are differentially activated by wound stress depending on the plant growth stage, and that the antioxidative enzymes are activated by wounding in two phases. The first phase involves activation of superoxide dismutase and peroxidase and rapid deactivation of catalase. The second phase involves deactivation of peroxidase under conditions of severe stress. Deactivation of peroxidase and catalase may lead to accumulation of hydrogen peroxide, which can activate of a series of additional defense mechanisms. [Copyright &y& Elsevier]

Wound stress activated wheat root cells to produce oxygen radicals. The production was accompanied by an increased permeability for potassium ions and a depolarization of the plasma membrane. Various electron donors, such as the nonpenetrating donor potassium ferrocyanide as well as NADH and NADPH, caused the amplification of superoxide production by root cells. The $$O_2 ^{. - } $$ -generating system in wheat root cells was found to be considerably sensitive to diphenylene iodonium, which is generally considered as a suicide inhibitor of neutrophil NADPH oxidase, and to other inhibitors of flavoprotein activity, chlorpromazine and quinine. The xenobiotic compound amidopyrine caused activation of the $$O_2 ^{. - } $$ -generating system, which was depressed by DPI. The $$O_2 ^{. - } $$ -generating system in root cells was shown to be significantly dependent on calcium content. Calcium loading of the root cells induced a powerful increase of the superoxide release. Data obtained indicate that superoxide generation is one of the early events of the wound stress response. Redox systems of the plasma membrane may be involved in the superoxide production in response to wound stress and detoxification of xenobiotic compounds in root cells. [ABSTRACT FROM AUTHOR]

Plant growth, development and phenotypic plasticity are highly influenced by the genetic composition of a plant, environment, and genetic by environment interactions. The role of intraspecific genetic variance and environmental variations in mediating responses of commercially important crops such as sugarcane to wound stress is, however, poorly understood. Therefore, we utilized 10 sugarcane genotypes cultivated in different common gardens, and subsequently wounded to assess the influence of genotype by environment interaction on the expression profiles of sugarwin1 , a potent defense-responsive gene that is predominantly expressed in response to wounding. We found that, genotypes (G10, G6, G7) had higher transcript patterns of sugarwin1 in comparison with (G1,G3,G2, G4) and (G5, G9, G8) which had intermediate, and relatively low levels, respectively; these results imply that, genotype by environment interaction, at least partially, underlie the genetic responses of sugarcane to wound stress. In addition, the results suggest that some sugarcane genotypes may have evolved impressive mechanisms to adapt to rapidly changing environments. Our findings, however, do not exclude the input of other factors such as epigenetics, which modulate gene expression in response to environment. Overall, the findings have implications in plant evolutionary responses to changing environments, and also in breeding approaches for sugarcane crop genetic improvement. • Sugarwin1 is essential for wounding stress responses. • Genotype by environment interactions modulate sugarcane molecular responses. • Helpful for screening of sugarcane genotypes that are better adapted to wound stress across multiple environments. [ABSTRACT FROM AUTHOR]