Low light and low ammonium are key factors for guayule leaf tissue shoot organogenesis and transformation

Dong, Ning; Montanez, Belen; Creelman, Robert A.; Cornish, Katrina

doi:10.1007/s00299-005-0024-2

Cited by 18 publications

(9 citation statements)

References 55 publications

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“…The transformed Agrobacterium EHA101 strains were used to transform guayule cultivar G7-11 following Dong et al (2013). The expression of the GUSplus reporter gene in the pND6 transformed guayule plants was confirmed by histochemical staining (Dong et al, 2006).…”

Section: Methodsmentioning

confidence: 99%

Downregulation of a CYP74 Rubber Particle Protein Increases Natural Rubber Production in Parthenium argentatum

et al. 2019

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We report functional genomics studies of a CYP74 rubber particle protein from Parthenium argentatum , commonly called guayule. Previously identified as an allene oxide synthase (AOS), this CYP74 constitutes the most abundant protein found in guayule rubber particles. Transgenic guayule lines with AOS gene expression down-regulated by RNAi ( AOSi ) exhibited strong phenotypes that included agricultural traits conducive to enhancing rubber yield. AOSi lines had higher leaf and stem biomass, thicker stembark tissues, increased stem branching and improved net photosynthetic rate. Importantly, the rubber content was significantly increased in AOSi lines compared to the wild-type (WT), vector control and AOS overexpressing ( AOSoe ) lines, when grown in controlled environments both in tissue-culture media and in greenhouse/growth chambers. Rubber particles from AOSi plants consistently had less AOS particle-associated protein, and lower activity (for conversion of 13-HPOT to allene oxide). Yet plants with downregulated AOS showed higher rubber transferase enzyme activity. The increase in biomass in AOSi lines was associated with not only increases in the rate of photosynthesis and non-photochemical quenching (NPQ), in the cold, but also in the content of the phytohormone SA, along with a decrease in JA, GAs, and ABA. The increase in biosynthetic activity and rubber content could further result from the negative regulation of AOS expression by high levels of salicylic acid in AOSi lines and when introduced exogenously. It is apparent that AOS in guayule plays a pivotal role in rubber production and plant growth.

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Section: Methodsmentioning

confidence: 99%

Downregulation of a CYP74 Rubber Particle Protein Increases Natural Rubber Production in Parthenium argentatum

et al. 2019

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“…The environment modulates shoot organogenesis. In particular, studies conducted in multiple plant species have demonstrated that week(s) of light or dark treatments after tissue excision can have profound effects on shoot regeneration (Dong et al . 2006).…”

Section: Introductionmentioning

confidence: 99%

“…1999, 2004; Saitou, Hashizume & Kamada 2000; Qin et al . 2005), blue/UV‐A light photoactivation (Bertram & Lercari 2000; Hunter & Burritt 2004) and photo‐oxidative damage (Dong et al . 2006).…”

Section: Introductionmentioning

confidence: 99%

The shoot regeneration capacity of excised Arabidopsis cotyledons is established during the initial hours after injury and is modulated by a complex genetic network of light signalling

Nameth

Dinka

Chatfield

et al. 2012

Plant Cell & Environment

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Excised plant tissues (explants) can regenerate new shoot apical meristems in vitro, but regeneration rates can be inexplicably variable. Light affects rates of shoot regeneration, but the underlying mechanisms are poorly understood. Here, excised Arabidopsis cotyledons were dark-light shifted to define the timing of explant light sensitivity. Mutants and pharmacological agents were employed to uncover underlying physiological and genetic mechanisms. Unexpectedly, explants were most light sensitive during the initial hours post-excision with respect to shoot regeneration. Only~100 mmol m -2 s -1 of fluorescent light was sufficient to induce reactive oxygen species (ROS) accumulation in new explants. By 48 h post-excision, induction of ROS, or quenching of ROS by xanthophylls, increased or decreased shoot regeneration, respectively. Phytochrome A-mediated signalling suppressed light inhibition of regeneration. Early exposure to blue/UV-A wavelengths inhibited regeneration, involving photoreceptor CRY1. Downstream transcription factor HY5 mediated explant photoprotection, perhaps by promoting anthocyanin accumulation, a pigment also induced by cytokinin. Surprisingly, early light inhibition of shoot regeneration was dependent on polar auxin transport. Early exposure to ethylene stimulated dark-treated explants to regenerate, but inhibited light-treated explants. We propose that variability in longterm shoot regeneration may arise within the initial hours post-excision, from inadvertent, variable exposure of explants to light, modulated by hormones.

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“…Light, a critical environmental signal, also modulates shoot regeneration, and has profound developmental effects on shoot organogenesis [ 17 ]. After tissue excision, low or high intensity light treatment can affect shoot regeneration in multiple plant species [ 18 ]. Arabidopsis explants are typically placed in continuous darkness or white light immediately after excision [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

“…High intensity light reduces the ability for shoot regeneration in Arabidopsis explants in vitro. Previous studies found that light affects multiple signaling pathways involving auxin [ 21 ], cytokinin [ 22 ], ethylene [ 23 ], red/far-red light photoactivation [ 24 , 25 ], blue/UV-A light photoactivation [ 26 ], and photo-oxidative damage [ 18 ]. Shoot regeneration was inhibited by treatment with 24 h blue/UV-A wavelengths after organ excision, while far red light signaling counteracts the inhibitory effects on shoot regeneration of early high intensity light exposure [ 20 ].…”

Section: Introductionmentioning

confidence: 99%

Early Low-Fluence Red Light or Darkness Modulates the Shoot Regeneration Capacity of Excised Arabidopsis Roots

Ding

Wang

et al. 2020

Plants

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In plants, light is an important environmental signal that induces meristem development and interacts with endogenous signals, including hormones. We found that treatment with 24 h of low-fluence red light (24 h R) or 24 h of darkness (24 h D) following root excision greatly increased the frequency of shoot generation, while continuous low-fluence red light in callus and shoot induction stages blocked the explants’ ability to generate shoots. Shoot generation ability was closely associated with WUS expression and distribution pattern. 1-N-naphthylphtalamic acid (NPA) disrupted the dynamic distribution of the WUS signal induced by early 24 h R treatment, and NPA plus 24 R treatment increased the average shoot number compared with early 24 h R alone. Transcriptome analysis revealed that differentially expressed genes involved in meristem development and hormone signal pathways were significantly enriched during 24 R or 24 D induced shoot regeneration, where early 24 h R or 24 h D treatment upregulated expression of WOX5, LBD16, LBD18 and PLT3 to promote callus initiation and formation of root primordia, and also activated WUS, STM, CUC1 and CUC2 expression, leading to initiation of the shoot apical meristem (SAM). This finding demonstrates that early exposure of explants to transient low-fluence red light or darkness modulates the expression of marker genes related with callus development and shoot regeneration, and dynamic distribution of WUS, leading to an increased ability to generate shoots.

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Low light and low ammonium are key factors for guayule leaf tissue shoot organogenesis and transformation

Cited by 18 publications

References 55 publications

Downregulation of a CYP74 Rubber Particle Protein Increases Natural Rubber Production in Parthenium argentatum

Downregulation of a CYP74 Rubber Particle Protein Increases Natural Rubber Production in Parthenium argentatum

The shoot regeneration capacity of excised Arabidopsis cotyledons is established during the initial hours after injury and is modulated by a complex genetic network of light signalling

Early Low-Fluence Red Light or Darkness Modulates the Shoot Regeneration Capacity of Excised Arabidopsis Roots

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