67 research outputs found
Expression of Spcdc25 and Arath;WEE1 in Arabidopsis alters the response of hypocotyl explants to auxin & cytokinin in culture
No full textEspressione dei geni GUS e UGT85A in Arabidopsis thaliana
No full textLe β-glucuronidasi (GUS) sono enzimi che catalizzano l’idrolisi del legame glicosidico fra l’acido β-glucuronico e altre molecole e sono suddivise in due famiglie: glicosil-idrolasi 2 e glicosil-idrolasi 79. Le β-glucuronidasi della famiglia 2, alle quali appartiene il GUS di E. coli largamente usato come gene reporter nei vegetali, sono note in un grande range di organismi, ma sembrano essere assenti nelle piante, nelle quali l’attività GUS endogena sembra associata a β-glucuronidasi della famiglia 79 (Eparanasi) (1).
In Arabidpopsis thaliana sono stati identificati e parzialmente caratterizzati tre diversi geni GUS (AtGUS1, AtGUS2 e AtGUS3), dei quali AtGUS1 e AtGUS2 mostrano elevata omologia.
A parte funzioni specifiche (2),coinvolgimento delle β-glucuronidasi è stato proposto nel processo di accrescimento cellulare per distensione e, in particolare, nell’allungamento dei peli radicali (3). E’ stato, inoltre, ipotizzato che β-glucuronidasi, agendo in coordinazione con glucuronisiltrasferasi (UGT) del gruppo 85A, siano responsabili della regolazione del ciclo cellulare (4,5). Uno studio più recente tuttavia ha messo in parte in discussione quanto emerso in precedenza riportando che nelle radici di plantule di Arabidopsis thaliana non è presente attività β-glucuronidasica (6).
In questo lavoro si è voluto approfondire lo studio dell’espressione dei geni GUS e UGT in Arabidopsis. Verifiche preliminari effettuate con PCR semiquantitativa hanno mostrato che, nonostante il gene AtGUS2 risulti espresso in modo più rilevante rispetto a AtGUS1 e AtGUS3, tutti e tre i geni AtGUS sono espressi, sia pure differenzialmente, in tutti gli organi della pianta. I geni AtUGT85A mostranoun pattern di espressione più differenziato rispetto ai geni AtGUS. AtUGT85A1, AtUGT85A2 e AtUGT85A4 risultano differenzialmente espressi nei vari organi della pianta, mentre AtUGT85A3 e UGT85A7 mostrano un’espressione organo specifica che coinvolge fiore e foglia
Utilizzando la tecnica di ibridazione in situ con sonde multiple recentemente messa a punto su campioni vegetali (7), l’espressione dei geni GUS è stata studiata anche a livello tissutale. A livello radicale , il pattern di espressione dei tre geni analizzati appare chiaramente differenziato: AtGUS1 e AtGUS2 sono espressi nell’epidermide, nella zona corticale e nella cuffia, mentre l’espressione di AtGUS3 è limitata all’epidermide. Sono in corso le analisi relative agli altri organi della pianta e, in particolare, fiore e polline. Analogo approccio verrà esteso ai geni AtUGT85 al fine di verificarne l’overlapping o meno con i domini istologici di espressione dei geni GUS e definirne eventuali correlazioni
Simultaneous characterisation of Prunus persica L. fruit volatilome and gene expression profile for a better understanding of molecular mechanisms underlying changes of peach during post-harvest storage
No full textIn Arabidopsis thaliana Cd differentially impacts on hormone genetic pathways in the methylation defective ddc mutant compared to wild type
No full textDNA methylation plays an important role in modulating plant growth plasticity in response to stress, but mechanisms involved in such control need further investigation. We used drm1 drm2 cmt3 mutant of Arabidopsis thaliana, defective in DNA methylation, to explore metabolic pathways downstream
epigenetic modulation under cadmium (Cd) stress. To this aim, a transcriptomic analysis was performed on ddc and WT plants exposed to a long-lasting (21 d) Cd treatment (25/50 μM), focusing on hormone genetic pathways. Growth parameters and hormones amount were also estimated.
Transcriptomic data and hormone quantification showed that, under prolonged Cd treatment, level and signalling of growth-sustaining hormones (auxins, CKs, GAs) were enhanced and/or maintained,
while a decrease was detected for stress-related hormones (JA, ABA, SA), likely as a strategy to avoid the side effects of their long-lasting activation. Such picture was more effective in ddc than WT, already at 25 μM Cd, in line with its better growth performance. A tight relationship between
methylation status and the modulation of hormone genetic pathways under Cd stress was assessed. We propose that the higher genome plasticity conferred to ddc by DNA hypomethylated status underlies its prompt response to modulate hormones genetic pathways and activity and assure a flexible growth
Common and genotype-specific responses of peach cultivars to chilled storage based on transcriptomic analysis
No full textMolecular and cytophysiological events underlying ectopic morphogenesis (epiphylly) in a somaclonal variant of interspecific hybrid Helianthus annuus L. x H. tuberosus
No full textAugmented analysis of sensorial, volatilome and gene expression data from peach cultivars during cold storage to identify markers for fruit quality
No full textPeach (Prunus persica (L. Batsch) produces high quality but perishable fruit appreciated for their
distinctive aroma, and other organoleptic qualities including sweetness, colour, and texture
which vary across different cultivars. Peaches are produced commercially in warmer temperate
regions such as Southern Europe, and frequently exported to Northern Europe. Due to the long
travel distances and complex supply chains peach fruit are transported cold to delay ripening
and spoilage. However long periods of cold storage can result in chilling injury and loss of quality.
Our understanding of how cold storage affects quality across different varieties can be explored
through different approaches. Here effects were assessed in one peach ('Sagittaria') and one
nectarine cultivar ( 'Big Top') through volatilome fingerprinting combined with gene expression
profiling. For analysis of the volatile organic compounds (VOCs) contributing to the volatilome,
we applied two-dimensional gas chromatography (GC×GC) combined with time-of-flight mass
spectrometry (TOF-MS), as well as sensorial analysis. RNA-sequencing was applied to identify
differentially expressed genes (DEGs) during post-harvest storage focusing on genes associated
with VOCs. Peach fruits were analysed at harvest and during 14 days of cold storage at 1°C.
Different numbers of VOCs were identified in the two cultivars: of 159 from ‘Sagittaria’, and 89
from ‘Big Top’ fruit. Canonical Analysis of Principal coordinates (or CAP) was able to discriminate
amongst VOC profiles from the two cultivars and across post-harvest storage time points. A
multitrait analysis of sensory, VOC and gene expression data supported the analysis based only
on VOCs showing correlations between the expression profiles of VOC-related genes and VOC
abundance. These data are of potential use to peach breeders for improving cold storage
resilience in relation to sensory changes, and could form the basis for markers of use in assessing
fruit quality through the supply chain
Fruit volatilome profiling through GC × GC-ToF-MS and gene expression analyses reveal differences amongst peach cultivars in their response to cold storage
No full textPeaches have a short shelf life and require chilling during storage and transport. Peach aroma is important for consumer preference and determined by underlying metabolic pathways and gene expression. Differences in aroma (profiles of volatile organic compounds, VOCs) have been widely reported across cultivars and in response to cold storage. However, few studies used intact peaches, or used equilibrium sampling methods subject to saturation. We analysed VOC profiles using TD‑GC × GC‑ToF‑MS and expression of 12 key VOC pathway genes of intact fruit from six cultivars (three peaches, three nectarines) before and after storage at 1 °C for 7 days including 36 h shelf life storage at 20 °C. Two dimensional GC (GC × GC) significantly enhances discrimination of thermal desorption gas chromatography time‑of‑flight mass spectrometry (TD‑GC‑ToF‑MS) and detected a total of 115 VOCs. A subset of 15 VOCs from analysis with Random Forest discriminated between cultivars. Another 16 VOCs correlated strongly with expression profiles of eleven key genes in the lipoxygenase pathway, and both expression profiles and VOCs discriminated amongst cultivars, peach versus nectarines and between treatments. The cultivar‑specific response to cold storage underlines the need to understand more fully the genetic basis for VOC changes across cultivars
The KNOTTED-like genes of peach (Prunus persica L. Batsch) are differentially expressed during drupe growth and the class 1 KNOPE1 contributes to mesocarp development
No full textThe KNOTTED-like transcription factors (KNOX) contribute to plant organ development. The expression patterns of peach KNOX genes showed that the class 1 members act precociously (S1-S2 stages) and differentially during drupe growth. Specifically, the transcription of KNOPE1 and 6 decreased from early (cell division) to late (cell expansion) S1 sub-stages, whilst that of STMlike1, 2, KNOPE2, 2.1 ceased at early S1. The KNOPE1 role in mesocarp was further addressed by studying the mRNA localization in the pulp cells and vascular net at early and late Si. The message signal was first diffuse in parenchymatous cells and then confined to hypodermal cell layers, showing that the gene down-tuning accompanied cell expansion. As for bundles, the mRNA mainly featured in the procambium/phloem of collateral open types and subsequently in the phloem side of complex structures (converging bundles, ducts). The KNOPE1 overexpression in Arabidopsis caused fruit shortening, decrease of mesocarp cell size, diminution of vascular lignification together with the repression of the major gibberellin synthesis genes AtGA20ox1 and AtGA3ox1. Negative correlation between the expression of KNOPE1 and PpGA3ox1 was observed in four cultivars at S1, suggesting that the KNOPE1 repression of PpGA3ox1 may regulate mesocarp differentiation by acting on gibberellin homeostasis
Volatilome fingerprinting, transcriptomics and sensorial analysis of peach cultivars during cold storage: A multi-trait approach to identify predictive markers of food quality
No full textFruit quality is a key driver for consumers. Therefore, it is important to optimize product quality throughout the supply chain. Quality can be assessed visually through fruit colour and firmness, while sensorial analyses provide data on aroma, sweetness and acidity. However, fingerprinting the volatilome (the volatile organic compound (VOC) profile) combined with global analyses of gene expression profiles, through next generation sequencing, are useful tools for objective quality assessment. These can provide data related to the cultivar, and its growth location and post-harvest treatments. Peach (Prunus persica (L. Batsch) fruits deteriorate rapidly at ambient temperature therefore cold storage is widely used to delay post-harvest ripening of the fruit, however they also suffer from cold stress.
Here, the volatilome of one peach (cv. Sagittaria) and one nectarine (cv Big Top) was analysed using comprehensive two-dimensional gas chromatography (GC×GC) and time-of-flight mass spectrometry (TOF-MS). In parallel RNA-sequence transcriptomics was used to identify differentially expressed genes (DEGs) associated with VOC metabolism. Fruits were analysed at harvest, and after 1, 5, 7 and 14 days of storage at 1°C.
We identified 159 and 89 VOCs from cv. Sagittaria, and cv. Big Top fruit respectively. VOC profiles showed discrimination both between the cultivars and amongst post-harvest storage periods, when analysed using Canonical Analysis of Principal coordinates (CAP). Sensory evaluation supported results from the volatilome. Gene expression analysis of VOC-related genes also showed a good correlation with changes in VOCs profiles.
Overall Omics data from VOC profiles and gene expression, may be of value to breeders in their selection of specific traits relating to aroma and post-harvest resilience. These technologies can also have a potential value throughout the supply chain in developing objective diagnostic tests to monitor quality from producer to consumer
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