Here, the intensity and ratio of superoxide anion (O
2
•
), hydrogen peroxide (H
2
O
2
) and hydroxyl anion (OH
•-
) formation along the
in vitro
shootlets of four pear (
Pyrus communis
L.) ...rootstocks (i.e., Pyrodwarf, OH × F40, OH × F69 and OH × F333) were scrutinized under
E. amylovora
inoculation, over 144 hpi. Furthermore, following identifying the most tolerant and susceptible pear rootstocks (i.e., OH × F69 and OH × F40, respectively), the dynamic expression profiles of three ROS-scavenging enzymatic genes including superoxide dismutase (
SOD
), Catalase (
CAT
) and ascorbate peroxidase (
APX
) were elucidated in response to
E. amylovora
, over 96 hpi. The highest disease tolerance was observed in OH × F69, and OH × F333, Pyrodwarf and OH × F40 occupied the next descending positions, respectively. Furthermore, the O
2
•-
generation rates were almost similar in all the pears studied, though the accumulation of H
2
O
2
and OH
•-
and intensities thereof were considerably distinctive and significantly followed up the levels of disease resistance. Comparing to the controls (0 hpi), in both susceptible and tolerant pear rootstocks, transcription activity of
SOD
,
CAT
, and
APX
genes were overall stimulated with relatively high abundance over 24, 48, 72 and 96 hpi, though some fluctuations were also recorded. Our ROS results, altogether, indicated that
E. amylovora
is capable enough to stimulate ROS formation in pear, though its progress is extremely dependent upon the susceptibility ratio of the plant. Lastly, the particular expression patterns and different response time of three genes designated that pear rootstocks differentially activates genes encoding antioxidant enzymes to mitigate the possible damage of ROS during
E. amylovora
invasion.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Se cita por primera vez a la especie Campylomma verbasci (Meyer-Dür) (Heteroptera: Miridae: Phylinae: Nasocorini) para la Argentina y el Neotrópico. Se muestran imágenes de ejemplares colectados, así ...como también su planta huésped y los daños ocasionados, y se dan sus caracteres diagnósticos. Se comenta brevemente la importancia de la aparición de esta especie en el país y sus hábitos alimenticios.
Abstract
Background
We report an improved assembly and scaffolding of the European pear (Pyrus communis L.) genome (referred to as BartlettDHv2.0), obtained using a combination of Pacific Biosciences ...RSII long-read sequencing, Bionano optical mapping, chromatin interaction capture (Hi-C), and genetic mapping. The sample selected for sequencing is a double haploid derived from the same “Bartlett” reference pear that was previously sequenced. Sequencing of di-haploid plants makes assembly more tractable in highly heterozygous species such as P. communis.
Findings
A total of 496.9 Mb corresponding to 97% of the estimated genome size were assembled into 494 scaffolds. Hi-C data and a high-density genetic map allowed us to anchor and orient 87% of the sequence on the 17 pear chromosomes. Approximately 50% (247 Mb) of the genome consists of repetitive sequences. Gene annotation confirmed the presence of 37,445 protein-coding genes, which is 13% fewer than previously predicted.
Conclusions
We showed that the use of a doubled-haploid plant is an effective solution to the problems presented by high levels of heterozygosity and duplication for the generation of high-quality genome assemblies. We present a high-quality chromosome-scale assembly of the European pear Pyrus communis and demostrate its high degree of synteny with the genomes of Malus x Domestica and Pyrus x bretschneideri.
•Pears were stored in dynamic controlled atmosphere (DCA) and extremely low oxygen.•Storage in CA delays the development of buttery and juicy texture of ‘Rocha’ pears.•Dynamic CA and extremely low O2 ...affect the majority of VOCs in the three cultivars.•Ripening of ‘Santa Maria’ pears is not inhibited after storage in DCA plus 7 d at 20 °C.•Ripening of ‘Packham's’ pears developed after storage in ELO and DCA plus 7 d shelf life.
The effects of controlled atmosphere (CA), extremely low oxygen (ELO), dynamic controlled atmosphere monitored by respiratory quotient (DCA-RQ) and carbon dioxide production (DCA-CD) on the quality and volatile organic compounds (VOCs) of ‘Santa Maria’, ‘Rocha’ and ‘Packham's’ pears were evaluated. All pear cultivars were stored at -0.5 °C, in CA (2 kPa O2), ELO (0.5 kPa O2), DCA-RQ, and DCA-CD, all under 1.0 kPa CO2. ‘Santa Maria’ pears were stored for 4 months and ’Rocha’ and ‘Packham's’ for 6 months, followed by 7 days at 20 °C before quality analyses. Storage of ‘Santa Maria’ and ‘Packham's’ pears under CA resulted in yellower fruit skin color and lower flesh firmness, compared to ELO, DCA-RQ and DCA-CD, which can be attributed to higher ethylene production and respiration rate, indicated by principal component analysis (PCA), as both variables are correlated with CA and are inversely correlated with skin color and flesh firmness. ‘Rocha’ pears stored under CA resulted in higher flesh firmness, which may be related to higher ethanol concentration, evidenced by PCA, where both variables are correlated with CA storage. Storage in DCA-RQ and DCA-CD resulted in higher ethyl acetate and butyl acetate concentrations in ‘Santa Maria’ pears, while in ‘Rocha’ pears lower ethyl acetate, butyl acetate, hexyl acetate, methyl acetate, pentyl acetate, and propyl acetate concentrations, and in ‘Packham's’ lower hexyl acetate and methyl acetate concentrations were observed, compared to CA storage. ‘Santa Maria’ pears, irrespective of storage condition and ‘Packham's’ pears in CA, develop a yellowish skin color, with buttery and juicy texture. The concentration of the vast majority of VOCs is reduced by storage in ELO, DCA-RQ and DCA-CD in the three cultivars.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Near infrared (NIR) spectroscopy allows rapid estimation of quality traits in fresh fruit. Several portable spectrometers are available in the market as a low-cost solution to perform NIR ...spectroscopy. However, portable spectrometers, being lower in cost than a benchtop counterpart, do not cover the complete near infrared (NIR) spectral range. Often portable sensors either use silicon-based visible and NIR detector to cover 400–1000 nm, or InGaAs-based short wave infrared (SWIR) detector covering the 900–1700 nm. However, these two spectral regions carry complementary information, since the 400–1000 nm interval captures the color and 3rd overtones of most functional group vibrations, while the 1st and the 2nd overtones of the same transitions fall in the 1000–1700 nm range. To exploit such complementarity, sequential data fusion strategies were used to fuse the data from two portable spectrometers, i.e., Felix F750 (~400–1000 nm) and the DLP NIR Scan Nano (~900–1700 nm). In particular, two different sequential fusion approaches were used, namely sequential orthogonalized partial-least squares (SO-PLS) regression and sequential orthogonalized covariate selection (SO-CovSel). SO-PLS improved the prediction of moisture content (MC) and soluble solids content (SSC) in pear fruit, leading to an accuracy which was not obtainable with models built on any of the two spectral data set individually. Instead, SO-CovSel was used to select the key wavelengths from both the spectral ranges mostly correlated to quality parameters of pear fruit. Sequential fusion of the data from the two portable spectrometers led to an improved model prediction (higher R2 and lower RMSEP) of MC and SSC in pear fruit: compared to the models built with the DLP NIR Scan Nano (the worst individual block) where SO-PLS showed an increase in R2p up to 56% and a corresponding 47% decrease in RMSEP. Differences were less pronounced to the use of Felix data alone, but still the R2p was increased by 2.5% and the RMSEP was reduced by 6.5%. Sequential data fusion is not limited to NIR data but it can be considered as a general tool for integrating information from multiple sensors.
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•First time sequential modelling NIR data for fruit analysis is presented.•Data from two portable spectrometer was fused to improve predictive performance.•NIR and SWIR spectral ranges carry complementary information.•Sequential variable selection identified subset of complementary wavelengths.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Sprayable formulation of 1-methylcyclopropene (1-MCP) was tested as a preharvest application on European pears to determine the best timing and rate of 1-MCP application for maintaining fruit ...firmness and quality of trees during harvest and in storage after harvest. Two rates of 1-MCP, 0.06 and 0.13 g⋅L −1 active ingredient (a.i.) (minimum and maximum rates, respectively), were sprayed 1 week and 2 weeks before commercial harvest on two cultivars, Bosc and Comice, in 2017 and 2018. After 2 months in cold storage (0 ± 1 °C), differences in fruit firmness of both cultivars were observed among treatments. For ‘Bosc’, fruit treated with both rates 1 week before harvest were 50% firmer than nontreated control fruit. For ‘Comice’, fruit treated with the maximum rate both 2 weeks and 1 week before commercial harvest were 46% and 31% firmer than nontreated control fruit, respectively. However, after 4 months in storage, no differences in fruit firmness of both ‘Bosc’ and ‘Comice’ were observed among treatments. The sprayable 1-MCP application applied 2 weeks before commercial harvest also affected the fruit firmness on trees. The maximum rate of 1-MCP treatment consistently maintained the fruit firmness by 5.0 N compared with fruit treated with the minimum rate and nontreated controls. This effect was significant until 1 week after commercial harvest for both cultivars and until 2 weeks after commercial harvest for ‘Bosc’. The poststorage fruit firmness and overall eating quality of ‘Bosc’ were unaffected by the maximum rate of 1-MCP application as well as the extended harvest time. However, for ‘Comice’, the overall eating quality was negatively impacted by 1-MCP treatments. This study suggests that the maximum rate (0.13 g⋅L −1 a.i.) of 1-MCP application 2 weeks before commercial harvest maintains the fruit firmness of ‘Bosc’ for at least 2 weeks more and offers an extended harvest window for better preharvest management. Furthermore, this treatment improves the physiological fruit quality such as senescence scald during the poststorage period without significantly affecting the poststorage ripening of ‘Bosc’ after 4 months of storage.
Anthocyanin concentration is the key determinant for red skin color in pear fruit. However, the molecular basis for development of red skin is complicated and has not been well-understood thus far. ..."Starkrimson" (Pyrus communis L.), an introduced red pear cultivated in the north of China and its green mutant provides a desirable red/green pair for identification of candidate genes involved in color variation. Here, we sequenced and annotated the transcriptome for the red/green color mutant at three stages of development using Illumina RNA-seq technology. The total number of mapped reads ranged from 26 to 46 million in six libraries. About 70.11-71.95% of clean reads could be mapped to the reference genome. Compared with green colored fruit, a total of 2230 differentially expressed genes (DEGs) were identified in red fruit. Gene Ontology (GO) terms were defined for 4886 differential transcripts involved in 15 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Three DEGs were identified as candidate genes in the flavonoid pathway, LAR, ANR, and C3H. Tellingly, higher expression was found for genes encoding ANR and LAR in the green color mutant, promoting the proanthocyanidin (PA) pathway and leading to lower anthocyanin. MYB-binding cis-motifs were identified in the promoter region of LAR and ANR. Based on these findings, we speculate that the regulation of PA biosynthesis might be a key factor for this red/green color mutant. Besides the known MYB and MADS transcription families, two new families, AP2 and WRKY, were identified as having high correlation with anthocyanin biosynthesis in red skinned pear. In addition, qRT-PCR was used to confirm the transcriptome results for 17 DEGs, high correlation of gene expression, further proved that AP2 and WARK regulated the anthocyanin biosynthesis in red skinned "Starkrimson," and ANR and LAR promote PA biosynthesis and contribute to the green skinned variant. This study can serve as a valuable new resource laying a solid foundation for functional gene identification in the anthocyanin pathway of red-skinned pear and provide a good reference for relevant research on molecular mechanisms of color variation in other pear species.
•Fruit set and yield were increased when gibberellins were applied after petal fall, with a positive relationship with dose.•Applications of GA4+7+BA promoted higher fruit set & yield than GA3, being ...less dependent to the moment of application.•GA4+7+BA showed an additive effect when performing multiple applications.•Return bloom was slightly affected when gibberellins were applied after petal fall.
Commercial pear production has become increasingly difficult over the last decade, with low fruit set being one of the main factors leading to poor yield of pear orchards. The use of gibberellins to increase fruit set has been widely reported, but in most of the cases these applications are made at full bloom or right after a spring frost has occurred. However, the increase in fruit set due to early applications of gibberellins such as at full bloom is often lost at June drop. Aim of this study was to assess dose and timing of different gibberellin applications made after petal fall to improve the final fruit set in pear orchards. Four experiments were conducted during four years (2010–2013) in mature pear orchards with ‘Conference’ as the scion cultivar. Fruit set and yield were increased when gibberellins were applied after petal fall, with a positive relationship with dose. Applications of GA4+7+BA tended to promote higher fruit set and yield than GA3, and in addition, they were less dependent to the moment of application. GA4+7+BA showed an additive effect when performing multiple applications. Return bloom was slightly affected when gibberellins were applied after petal fall. The strategy that showed a better behavior to increase fruit set was GA4+7+BA at 500 mL·ha−1 at H + 14, which coincides with the weeks of the natural fruit drop.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Melatonin limited, not promoted ethylene bursts, in the senescence of pear fruit.•Melatonin prevented mature pear fruit from undergoing physiological disorders.•Melatonin has the potential to retain ...the commercial value of pear fruit.
Some pear (Pyrus communis L.) fruit show a certain resistance to ripening. Thus, postharvest cold storage is commonly used to accelerate their ripening process by promoting ethylene production. However, the enhanced ethylene biosynthesis also accelerates pear fruit senescence. Here, the effects of melatonin on the senescence process in pear fruit was investigated. In a rapidly softening pear ‘Starkrimson’, melatonin delayed the ethylene burst. In ‘Abbé Fetel’ and ‘Red Anjou’, normally softening pears, melatonin inhibited ethylene production during the entire senescence process. The limited ethylene production resulted in a lower loss of firmness in melatonin-treated fruit than in water treated fruit. PcPG, a major cell wall degradation-related gene, was inhibited by melatonin in all three cultivars. The expressions of ethylene biosynthesis genes PcACS1 and PcACO1 are correlated with the senescence process. The former was inhibited by melatonin in ‘Starkrimson’, both were inhibited in ‘Red Anjou’, but neither was inhibited in ‘Abbé Fetel’. Moreover, the antioxidant systems in ‘Starkrimson’ and ‘Abbé Fetel’ were enhanced by melatonin and their fruit did not undergo water soaking or core browning. Thus, melatonin has the potential to retain the commercial value of postharvest pear fruit and delay senescence by limiting ethylene production and the reactive oxygen burst.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•ASM dipping decreased ethylene release in pear fruit.•ASM modulated the AsA-GSH cycle to delay senescence of pears.•The exocarp of pears responded more rapidly than the mesocarp to ASM treatment.
...This study was conducted to explore the changes of quality indicators and ascorbate-glutathione (AsA-GSH) cycle in 'Docteur Jules Guyot' pears after acibenzolar-S-methyl (ASM) dipping. Results demonstrated that ASM delayed the yellowing and flesh firmness decline, decreased the ethylene release and titratable acidity, and increased soluble solid content in pears. Additionally, ASM enhanced the hydrogen peroxide, ascorbic acid, and reduced glutathione contents, improved the activities of ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase, and dehydroascorbate reductase in the exocarp and mesocarp of pears. However, enzymes activities and hydrogen peroxide content in the exocarp were higher than that in the mesocarp after dipping with ASM. These results suggest that postharvest application of ASM could modulate the AsA-GSH cycle to delay senescence of pears, and the exocarp responded more rapidly than the mesocarp.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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