•Waterlogging would cause the generation of adventitious roots of Cannas.•The D value works as the evaluation of waterlogging-tolerent ability of Cannas.•11 Canna cultivars were classified due to ...waterlogging tolerance via cluster analysis.•Physiological indexes related to waterlogging tolerance of Cannas were screened out.•Among the 11 Canna cultivars, Mohong is the most waterlogging tolerant.
To identify and screen the waterlogging-tolerant cultivars of Canna spp. and establish a comprehensive, mathematical evaluation model of Canna plants, morphological characteristics and physiological indices were recorded and measured using the leaves of 11 cultivars. Their waterlogging tolerance was overall evaluated by calculating the waterlogging injury index (WII) and waterlogging tolerance coefficient (WTC) based on the morphological traits and physiological indices. Results revealed that after waterlogging stress, adventitious roots appeared in all cultivars, whose length and number increased as the stress persisted. Among the tested species, there were more adventitious roots observed in C. edulis Ker, C. waracewiezii Dietr. and C. orchioides Bailey., while C. indica L., C. flaccida Salisb., and C. generalis Bailey. had few adventitious roots. Additionally, the edges of the lower leaves of C. edulis Ker. cv. ‘PLRF’, ‘Xingyu-1′, ‘Xingyu-2′ and C. orchioides Bailey. cv. ‘Sajin’ yellowed the most and experienced the worst scorch. Damage was less obvious on C. generalis Bailey. cv. ‘Mohong’ leaves after waterlogging stress for 21 d Furthermore, ‘Mohong’ was determined to be the most waterlogging tolerant cultivar and had the lowest WII value (0.400), while the ‘PLRF’ had the highest (0.840) and clustered into the waterlogging-sensitive group. Four physiological indices, including catalase (CAT), peroxidase (POD), soluble sugar (SS) and malonaldehyde (MDA) increased (WTC > 1) after waterlogging, while soluble protein (SP) decreased (WTC < 1) in all cultivars. Changes in the activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX) differed among cultivars. Principal component analysis (PCA) transformed the 7 physiological indices into 4 independent, comprehensive indices, whose cumulative contribution ratio reached 96.062%. The 11 cultivars were divided into 4 categories based on the comprehensive evaluation value (D). ‘Mohong’, in the waterlogging-tolerant group had the highest D value (0.912). C. waracewiezii Dietr. cv. ‘Ziye Xiaojuhong’, C. generalis Bailey. cv. ‘Grand Due’, C. orchioides Bailey. cv. ‘Suihua Chenghong’ and C. indica L. belonged to the intermediate waterlogging-tolerant group with D values of 0.652, 0.616, 0.590 and 0.533, respectively. C. orchioides Bailey. cv. ‘Lüyecheng’, C. flaccida Salisb. cv. ‘Yellow Canna’, ‘Xingyu-1′ and ‘Xingyu-2′ were clustered into the low waterlogging-tolerant group with the D values of 0.458, 0.455, 0.421 and 0.368, respectively. Lastly, ‘Sajin’ and ‘PLRF’ clustered into the sensitive waterlogging tolerant group with the lowest D value of 0.201 and 0.170, respectively. The stepwise regression analysis showed that CAT, POD, SOD, APX, SS and MDA, can be used to evaluate and predict the waterlogging tolerance of different Canna lily cultivars.
Stem cuttings of the endangered ancient Platycladus orientalis are a valuable genetic resource for cryopreservation and propagation, but their extremely hard adventitious root (AR) formation poses a ...challenge for regeneration. In this study, we investigated the causes of decreased AR formation during the initial stem (S1), callus expansion (S2), and AR formation (S3) stages in cuttings from 5-, 100-, and 700-year-old P. orientalis trees, and identified potential solutions to enhance AR formation. Proteomic analysis revealed an up-regulation of flavonoid and phenylpropanoid biosynthesis pathway-associated proteins, including chalcone synthase (CHS), chalcone isomerase (CHI), and flavonone-3-hydroxylase (F3H), as well as down-regulation of auxin transport-associated proteins, such as auxin transport protein (BIG) and auxin responsive (AIR12), in the S3 of 700-year-old donors cuttings. Subsequent biochemical analysis confirmed over-accumulation of flavonoids, phenolics, and lignin resulting in callus-lignification and inhibition of AR formation in 100- and 700-year-old donors. Notably, wounding of the lignified-callus significantly increased AR formation in cuttings of 100-year-old donors. The upregulation of expression of meristematic cells regulatory proteins (enolase (ENO) and elongation factor 1α (EF1α)), carbohydrate metabolism proteins (isoamylases (ISA)), and vitamin B6 biosynthesis proteins (pyridoxine synthase (PDX1) and pyridoxal kinase (PDXK)) after wounding, might promote AR formation in the lignified-callus with wounding of cuttings of 100-year-old donors. Overall, our findings reveal that callus-lignification inhibits AR formation, while wounding promotes it in ancient P. orientalis. This study provides a foundation for enhancing the rooting rate and shortening the rooting time in ancient P. orientalis, and potentially other difficult-to-root species.
•Flavonoid and phenylpropanoid biosynthesis associated proteins were up-regulated during adventitious root (AR) formation.•Lignification of callus inhibited AR formation of stem cuttings propagated from ancient trees.•Wounding stimulated the biosynthesis of vitamin B6, starch and sucrose, which might promote AR formation in cuttings.
Grapevine (Vitis sp.) is one of the most important economic fruit crops all over the world, and the formation of adventitious roots (ARs) is crucial for the vegetative reproduction of grapes. ...However, studies on the regulatory mechanisms of this process are currently lacking. In this study, we applied an efficient and convenient leave-petiole (LP) system for studying ARs, revealing a significant inhibition of root primordia formation under continuous-light treatment. The results showed that isolated ARs of grapevine were induced and originated from ray cells near the vascular cambium, with the process categorized into induction, initiation, and extension stages. LP samples under light and dark conditions were used for transcriptome sequencing and endogenous hormone measurements at three critical time points of AR formation. A total of 37 155 transcripts were obtained, and 7041 genes showed significantly different expression levels in the petiole. An integrated analysis, including Gene Ontology (GO) enrichment analysis, weighted gene co-expression network analysis (WGCNA), and hormonal content determination, showed that several genes (ARF4, LAX1, PIN1, SUS2, APX1, TPXL1, CHS3, etc.) associated with hormone signals, sugar synthesis and transport, reactive oxygen species (ROS) scavenging, cell wall biogenesis, flavonoid biosynthesis, microtubule remodeling, and some transcription factors (HY5, COP1, ERF2, MYB15, etc) played vital roles in light-induced AR formation. A hypothetical model was initially constructed, which illustrated the centrality of auxin in HY5-dependent AR formation and the complex crosstalk among various factors. The results of this study provided abundant genetic resources and a novel perspective for understanding the molecular mechanisms of AR formation in grapevine.
•Exogenous Spd application promoted AR formation.•Spd improved the concentration of endogenous IAA and GA3 as well as decreased the ABA and JA contents.•Spd application up-regulated the expression of ...Spd related genes and auxin biosynthesis related genes.
Adventitious root (AR) formation is a critical process for the clonal propagation of horticultural crops. Polyamines are involved in several processes associated with root growth such as cell division and cell development. In this study, Malus prunifolia var. ringo stem cuttings were treated with exogenous spermidine (Spd) 20 μmol/L in order to investigate the physiological and molecular mechanism of Spd to promote ARs formation. The results of the present study indicated an involvement of Spd in AR formation in apple rootstock by interacting with IAA. Morphological and anatomical observation revealed that the Spd application promotes AR formation. According to our results exogenous Spd application promoted AR formation by improving the concentration of endogenous IAA and GA3 at 1, 3 and 1, 8 days respectively as well as by decreasing the ABA and JA contents at all time points except JA at 16 day in response to Spd treatment. Furthermore no significant difference was observed in BR and ZR levels at all time points except at 8 day in both groups. Spd application obviously up-regulated the expression of Spd related genes (MdSAMDC1, MdPAO and MdSPDS6) and auxin biosynthesis related genes (MdIAA7, MdIAA14 and MdIAA23) in the basal parts of apple rootstock. On the other hand MdWOX11 up-regulated the expression of MdLBD16 and MdLBD29, which induced the expression of cell cycle related genes MdCYCD1;1 and MdCYCP4;1. Collectively, our work laid the foundation for applied research and could be useful in future crop improvement programs.
Adventitious root (AR) formation is a complex genetic trait, which is controlled by various endogenous and environmental cues. Auxin is known to play a central role in AR formation; however, the ...mechanisms underlying this role are not well understood.
In this study, we showed that a previously identified auxin signaling module, AUXIN RESPONSE FACTOR(ARF)7/ARF19-LATERAL ORGAN BOUNDARIES DOMAIN(LBD)16/LBD18 via AUXIN1(AUX1)/LIKE-AUXIN3 (LAX3) auxin influx carriers, which plays important roles in lateral root formation, is involved in AR formation in Arabidopsis. In aux1, lax3, arf7, arf19, lbd16 and lbd18 single mutants, we observed reduced numbers of ARs than in the wild type. Double and triple mutants exhibited an additional decrease in AR numbers compared with the corresponding single or double mutants, respectively, and the aux1 lax3 lbd16 lbd18 quadruple mutant was devoid of ARs. Expression of LBD16 or LBD18 under their own promoters in lbd16 or lbd18 mutants rescued the reduced number of ARs to wild-type levels. LBD16 or LBD18 fused to a dominant SRDX repressor suppressed promoter activity of the cell cycle gene, Cyclin-Dependent Kinase(CDK)A1;1, to some extent. Expression of LBD16 or LBD18 was significantly reduced in arf7 and arf19 mutants during AR formation in a light-dependent manner, but not in arf6 and arf8. GUS expression analysis of promoter-GUS reporter transgenic lines revealed overlapping expression patterns for LBD16, LBD18, ARF7, ARF19 and LAX3 in AR primordia.
These results suggest that the ARF7/ARF19-LBD16/LBD18 transcriptional module via the AUX1/LAX3 auxin influx carriers plays an important role in AR formation in Arabidopsis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Adventitious root formation of tree peony can be divided into three stages: induction (0–10 d), initiation (10–15 d) and extension (15–30 d).•IAA is the most important promoting hormone, and changes ...in its content are closely related to adventitious root primordia.•ZR and GAs may act synergistically with IAA to regulate the formation and differentiation of adventitious root primordia.•ABA is related to the stress resistance of in vitro shoots.•Genes like GH3.6, SAUR23, PYL4, PYL11, PIF4, GDP1 and CRD regulate adventitious root formation through the combined regulation of endogenous IAA, GAs, ZR and ABA contents.
The difficulty of rooting is the bottleneck of micropropagation in tree peony. Endogenous hormone is the key factor to regulate adventitious roots formation, but the research on the exploration of its related mechanisms is still lagging. In this study, the changes in endogenous hormone content during adventitious root formation were investigated in Paeonia × lemoinei ‘High Noon’. Transcriptome sequencing was carried out at five key time points of rooting. The results showed that the in vitro adventitious roots of tree peony formed from induced root primordium, which mainly originated from vascular bundles. However, a few roots originated from the callus. The progress of adventitious root formation can be divided into three stages. IAA (3-Indoleacetic Acid), ZR (trans-Zeatin-riboside), and GAs (Gibberellins) were positively correlated with adventitious root primordia. The trend of ABA (Abscisic Acid) and IAA was opposite, and ABA is related to the stress resistance of in vitro shoots. Plant hormone signal transduction was identified as a key metabolic pathway regulating adventitious root formation. Twenty-eight key genes were mined in this pathway. Using weighted gene co-expression network analysis, 17 hub genes were identified in the co-expression network of hormone trait-related modules. Through a comprehensive analysis, a hypothesis model of endogenous hormones regulating adventitious root formation in tree peony was preliminarily constructed. The results of this study can provide rich genetic resources and a direction for further exploring the molecular mechanism of adventitious root formation in tree peony.
, a common horticultural tree species, has an extremely long life span and forms a graceful canopy. Its branches, leaves, and cones have been used in traditional Chinese medicine. However, difficulty ...in rooting is the main limiting factor for the conservation of germplasm resources. This study shows that the rooting rates and root numbers of cuttings were significantly reduced in ancient
donors compared to 5-year-old
donors. The contents of differentially accumulated metabolites (DAMs) in phenylpropanoid (caffeic acid and coniferyl alcohol) and flavonoid biosynthesis (cinnamoyl-CoA and isoliquiritigenin) pathways increased significantly in cuttings propagated from ancient
donors compared to 5-year-old
donors during adventitious root (AR) formation. These DAMs may prevent the ancient
cuttings from rooting, and gradual lignification of callus was one of the main reasons for the failed rooting of ancient
cuttings. The rooting rates of ancient
cuttings were improved by wounding the callus to identify wounding-induced rooting-promoting metabolites. After wounding, the contents of DAMs in zeatin (5'-methylthioadenosine,
-zeatin-
-glucoside, and adenine) and aminoacyl-tRNA biosynthesis (l-glutamine, l-histidine, l-isoleucine, l-leucine, and l-arginine) pathways increased, which might promote cell division and provided energy for the rooting process. The findings of our study suggest that breaking down the lignification of callus
wounding can eventually improve the rooting rates of ancient
cuttings, which provides a new solution for cuttings of other difficult-to-root horticultural and woody plants.
For most fruit and forest species vegetative propagated from elite genotypes, adventitious rooting is essential. The ability to form adventitious roots significantly decreased during the juvenile to ...adult phase change. Apart from the miR156-SPL pathway, whether there is another regulation mechanism controlling age-dependent adventitious rooting ability remained largely unknown. In the present study, we showed that
expression level was positively correlation with adventitious rooting ability. In addition, over-expressing of
in tobacco leads to enhanced adventitious rooting ability, more adventitious root number and accelerated adventitious rooting process. Comparative transcriptome profiling indicated that
overexpression can activate the expression of adventitious rooting-induced genes, such as
and
. In addition,
overexpression can inhibit the transcription of adventitious rooting-repressed genes, such as
and type-B cytokinin
. Collectively, here we demonstrated that higher expression level of
contributes to age-dependent adventitious rooting-competent in juvenile apple rootstock.
•Platycladus orientalis is one of the major ecological and medicinal plants.•Adventitious roots originated in multiple locations.•Tissue-specific accumulation of auxin promoted de novo root ...regeneration.•It is revealed developmental homeostasis of hormones during roots formation.
De novo root regeneration in stem cutting is essential for massive propagation of Platycladus orientalis (L.) Franco, which is one of the major ecological and economic tree species in China. However, the details of adventitious root (AR) formation and how it is controlled by inherent hormones are still ambiguous. In this study, histological analysis, immunohistochemical localization combined with quantitative hormonal analysis were conducted to investigate how cutting induces the AR formation of P. orientalis. It was explicitly seen that AR emerged from either calli- or non-calli- covered barks. The anatomical structure showed that cutting initiated the inducible formation of AR primordia in multiple sites, including xylem, phloem, medullary ray, and annulus randomly. The tissue-specific accumulations of indole-3-acetic acid (IAA) surged in cambia-derived calli, basal boundaries of AR primordia, and AR, supporting the idea that the mode action of auxin was key to diverse types of root organogenesis. Meanwhile, the data showed that similar to that of IAA, the contents of abscisic acid (ABA) and zeatin (ZT) peaked at early stages of AR formation and deceased gradually in both phloem and xylem across the later stages, suggesting their indispensable roles in AR initiation. On contrary, jasmonic acid (JA) roughly maintained at extremely high levels in phloem comparing with the xylem tissues thoroughly, indicating its presence was involved in phloem-specific reorganization during AR formation. Collectively, the results provide a time-course histological dissection of AR formation, revealing developmental homeostasis of four main endogenous hormones, and providing theoretically a potential way to improve performance of stem-cutting in P. orientalis through regulating hormone actions in the future.
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