Sherif Sherif

• PhD Plant Molecular Biology
• Associate Professor at Virginia Tech

Variations in floral display represent one of the core features associated with the transition from allogamy to autogamy in angiosperms. The promotion of autogamy under stress conditions suggests the potential involvement of a signaling pathway with a dual role in both flower development and stress response. The jasmonic acid (JA) pathway is a plau...

Ethylene, a key plant hormone, regulates various fruit ripening traits, including pre-harvest fruit drop (PFD) and color development. In commercially valuable apple cultivars like ‘Honeycrisp,’ excessive fruit drop before the commercial harvest date poses a significant challenge, leading to substantial crop losses. While ethylene inhibitors such as...

Glomerella leaf spot (GLS) and bitter rot caused by species in the Colletotrichum gloeosporioides species complex are the most economically devastating fungal diseases of apples in North Carolina. Crop losses have reached 100% in highly susceptible cultivars. In the southeastern United States, management of this disease has predominantly relied on...

Ethylene is an important phytohormone that orchestrates a multitude of physiological and biochemical processes regulating fruit ripening, from early maturation to post-harvest. This review offers a comprehensive analysis of ethylene’s multifaceted roles in climacteric fruit ripening, characterized by a pronounced increase in ethylene production and...

Salinity is one of the substantial threats to plant productivity and could be escorted by other stresses such as heat and drought. It impairs critical biological processes, such as photosynthesis, energy, and water/nutrient acquisition, ultimately leading to cell death when stress intensity becomes uncured. Therefore, plants deploy several proper p...

Like other plant stresses, salinity is a central agricultural problem, mainly in arid or semi-arid regions. Therefore, salt-adapted plants have evolved several adaptation strategies to counteract salt-related events, such as photosynthesis inhibition, metabolic toxicity, and reactive oxygen species (ROS) formation. European grapes are usually graft...

Low temperature stress significantly threatens crop productivity and economic sustainability. Plants counter this by deploying advanced molecular mechanisms to perceive and respond to cold stress. Transmembrane proteins initiate these responses, triggering a series of events involving secondary messengers such as calcium ions (Ca²⁺), reactive oxyge...

This study endeavors to explore the transcriptomic profiles of two apple cultivars, namely, ‘Honeycrisp’ and ‘Cripps Pink,’ which represent late and early-blooming cultivars, respectively. Using RNA-sequencing technology, we analyzed floral bud samples collected at five distinct time intervals during both endodormancy and ecodormancy. To evaluate t...

This study provides a thorough exploration of the mechanisms regulating the onset of flowering in peach trees, a process principally governed by bud-dormancy. We applied untargeted metabolomics combined with a comprehensive series of molecular and biochemical experiments to scrutinize the variations in bloom times among different peach cultivars. T...

The number of fruits that remain on an apple tree directly affects yield, fruit size and the quality of fruit that are harvested, which largely determines crop value. If the number of apples can be precisely managed the final crop value can be maximized. We are conducting a USA national SCRI project to develop precision crop load management strateg...

Camelina sativa is a self-pollinating and facultative outcrossing oilseed crop. Genetic engineering has been used to improve camelina yield potential for altered fatty acid composition, modified protein profiles, improved seed and oil yield, and enhanced drought resistance. The deployment of transgenic camelina in the field posits high risks relate...

Preharvest fruit drop is a significant physiological problem that affects numerous commercially significant apple varieties, including ‘Gala.’ AVG and 1-MCP are two plant growth regulators commonly used to reduce fruit drop by reducing ethylene synthesis and perception, respectively. To optimize yield and market acceptance, a complete investigation...

Bitter pit (BP) is a physiological disorder of apples that often appears during or after cold storage. Despite being defined as a calcium deficiency disorder, BP is a complex process that is not only affected by the total Ca²⁺ content in the fruit but also by the proper cellular Ca²⁺ homeostasis and partitioning. Early investigations have also sugg...

Ethephon (ET) is an ethylene-releasing plant growth regulator (PGR) that can delay the bloom time in Prunus, thus reducing the risk of spring frost, which is exacerbated by global climate change. However, the adoption of ET is hindered by its detrimental effects on tree health. Little knowledge is available regarding the mechanism of how ET shifts...

The Ascomycete Ophiostoma novo-ulmi threatens elm populations worldwide. The molecular mechanisms underlying its pathogenicity and virulence are still largely uncharacterized. As part of a collaborative study of the O. novo-ulmi-elm interactome, we analyzed the O. novo-ulmi ssp. americana transcriptomes obtained by deep sequencing of messenger RNAs...

Dutch elm disease (DED), caused by Ophiostoma novo-ulmi (Onu), is a destructive disease of American elm (Ulmus americana L.). The molecular mechanisms of resistance and susceptibility against DED in American elm are still largely uncharacterized. In the present study, we performed a de novo transcriptome (RNA-sequencing; RNA-Seq) assembly of U. ame...

Gills reportedly play a crucial role in induction of an antiviral immune response in fish. We investigated the expression of innate response genes in the rainbow trout gill epithelial cell line RTgill-W1 36 h after pretreatment with ultraviolet-inactivated viral hemorrhagic septicemia virus (UV-VHSV), flagellin C protein from Edwardsiella tarda (Fl...

In 2014, a multi-year orchard experiment of apple Malus domestica (Borkh) was established at 14 locations in Canada, Mexico, and the United States using 'Honeycrisp' as the scion. Seventeen dwarf and semi-dwarf rootstock genotypes were tested, specifically: Budagovsky.10 (B. Malling rootstocks M.7, MM.106, and the Vineland rootstocks V.1, V.5, V.6,...

Eight blueberry cultivars at three developmental stages were investigated for metabolite profiling, antioxidant, and anticancer activities. Cultivars-and developmental stages-variations were determined in total phenolic, flavonoid, DPPH, and FRAP antioxidant assays. The anticancer capacity was equal against A549, HepG2, and Caco-2 cancer cells, whe...

Ethephon (ET) is an ethylene-based plant growth regulator (PGR) that has demonstrated greater efficacy in delaying bloom in deciduous fruit species. However, the underlying mechanisms by which ET modulates dormancy and flowering time remain obscure. This study aimed to delineate the ET-mediated modulations of reactive oxygen species (ROS), antioxid...

Apple production in temperate regions is continuously imperiled by spring frosts. Economic losses caused by frost damage can be enormous, and the risk of such losses is projected to rise due to global climate change. Induction of bloom delay has been suggested as a potential frost avoidance strategy. However, applicable practices toward this goal a...

Understanding the biochemical mechanisms underlying bud dormancy and bloom time regulation in deciduous woody perennials is critical for devising effective strategies to protect these species from spring frost damage. This study investigated the accumulation profiles of carbohydrates, ROS and antioxidants during dormancy in ‘Cripps Pink’ and ‘Honey...

Understanding the biochemical mechanisms underlying bud dormancy and bloom time regulation in deciduous woody perennials is critical for devising effective strategies to protect these species from spring frost damage. This study investigated the accumulation profiles of carbohydrates, ROS and antioxidants during dormancy in ‘Cripps Pink’ and ‘Honey...

In the eastern USA and several other apple-growing regions, apple blossom thinning using lime sulfur is a relatively new crop load management strategy. This study sought to evaluate how application timing of lime sulfur + stylet oil blossom thinning sprays would influence thinning efficacy and crop safety of ‘Gala’ apples. This project occurred at...

In grafted plants, the movement of long-distance signals from rootstocks can modulate the development and function of the scion. To understand the mechanisms by which tolerant rootstocks improve scion responses to osmotic stress (OS) conditions, mRNA transport of osmotic responsive genes (ORGs) was evaluated in a tomato/potato heterograft system. I...

The growth and productivity of several apple rootstocks have been evaluated in various previous studies. However, limited information is available on their tolerance to osmotic stress. In the present study, the physiological and molecular responses as well as abscisic acid (ABA) levels were assessed in six apple rootstocks (M26, V3, G41, G935, B9 a...

Successful cropping of apple depends on the ability of trees in the orchard to undergo both a period of dormancy and to acclimate to low winter temperatures. These physiological processes are inter-connected and involve crosstalk via shared signal transduction pathway components, phytohormones, and the environment. However, these processes also pos...

Spring frosts exacerbated by global climate change have become a constant threat to temperate fruit production. Delaying the bloom date by plant growth regulators (PGRs) has been proposed as a practical frost avoidance strategy. Ethephon is an ethylene-releasing PGR found to delay bloom in several fruit species, yet its use is often coupled with ha...

Three muscadine grape genotypes (Muscadinia rotundifolia (Michx.) Small) were evaluated for their metabolite profiling and antioxidant activities at different berry developmental stages. A total of 329 metabolites were identified using UPLC-TOF-MS analysis (Ultimate 3000LC combined with Q Exactive MS and screened with ESI-MS) in muscadine genotypes...

Spray‐induced gene silencing (SIGS) using topical dsRNA applications has risen as a promising, target‐specific, and environmentally friendly disease management strategy against phytopathogenic fungi. However, dsRNA stability, efficacy, and scalability are still the main constraints facing SIGS broader application. Here we show that Escherichia coli...

‘Honeycrisp’ ( Malus × domestica) apples were harvested from a total of 17 mid-Atlantic orchards during 2018 and 2019 to verify a previously published bitter pit prediction model. As in the previous study, bitter pit incidence was associated with low calcium (Ca) levels and high ratios of nitrogen (N), potassium (K), and/or magnesium (Mg) to Ca in...

Fruit development is orchestrated by a complex network of interactions between hormone-signaling pathways. The phytohormone, gibberellin (GA), is known to regulate a diverse range of developmental processes; however, the mechanisms of GA-action in perennial fruit species are yet to be elucidated. In the current study, a GA-signaling gene PslSLY1, e...

Bud dormancy is an adaptive mechanism that is coordinated by a complex signaling network of multiple phytohormones, where abscisic acid (ABA) plays a pivotal role. Dormancy regulation at the biochemical level remains largely uncharacterized, especially as it relates to the role ABA homeostasis might play in dormancy induction, maintenance, and rele...

Global climate change has posed new challenges to the temperate fruit production in the Northern Hemisphere by increasing the occurrence of spring frosts and disturbing bud dormancy, a critical mechanism that deciduous woody perennials undergo to survive the subfreezing winter temperatures. Many management strategies have been proposed to mitigate...

In recent years, RNA interference (RNAi) machinery has widely been explored by plant biologists for its potential applications in disease management, plant development, and germplasm improvement. RNAi-based technologies have mainly been applied in the form of transgenic plant generation and host-induced-gene-silencing (HIGS). However, the approval...

Plant stress is a real dilemma; it puzzles plant biologists and is a global problem that negatively affects people’s daily lives. Of particular interest is salinity, because it represents one of the major water-related stress types. We aimed to determine the signals that guide the cellular-related events where various adaptation mechanisms cross-ta...

Botrytis cinerea is one of the most critical agro-economic phytopathogens and has been reported to cause gray mold disease in more than 1000 plant species. Meanwhile, small interfering RNA (siRNA), which induce RNA interference (RNAi), are involved in both host immunity and pathogen virulence. B. cinerea has been reported to use both siRNA effector...

The sustainable fruit production in temperate and boreal regions is often imperiled by spring frosts. The risk of frost damage and the resulting economic losses have been increasing in the recent years as a result of the global climate change. Among the many approaches in mitigating frost damages, an ethylene-based compound, ethephon has proven to...

Woody perennials enter seasonal dormancy to avoid unfavorable environmental conditions. Plant hormones are the critical mediators regulating this complex process, which is subject to the influence of many internal and external factors. Over the last two decades, our knowledge of hormone-mediated dormancy has increased considerably, primarily due to...

Maturity date (MD), defined as the duration between the first calendar day of the year and maturity, and fruit development period (FDP), defined as the duration between full bloom and maturity, are highly variable in peach [Prunus persica (L.) Batsch]. There is a need to discover molecular markers associated with these traits in order to enhance th...

Tolerance to Dutch elm disease (DED) has been linked to the rapid and/or high induction of disease-responsive genes after infection with the fungus Ophiostoma novo-ulmi. Although the fungal infection by O. novo-ulmi primarily takes places in xylem vessels, it is still unclear how xylem contributes to the defense against DED. Taking advantage of the...

Phosphatidylinositol 3-kinase (PI3K) is a key enzyme that phosphorylates phosphatidylinositol at 3’-hydroxyl position of the inositol head group initiating the generation of several phosphorylated phosphatidylinositols, collectively referred to as phosphoinositides. The function of PI3K in plant senescence and ethylene signal transduction process w...

American Elms were devastated by an outbreak of Dutch Elm Disease is caused by the fungus Ophiostoma novo-ulmi Brasier that originated in Asia and arrived in the early 1900s. In spite of decades of study, the specific mechanisms and disease resistance in some trees is not well understood. the fungus is spread by a number of species of bark beetles...

Fruit growth depends on highly coordinated hormonal activities. The phytohormone gibberellin (GA) promotes growth by triggering degradation of the growth-repressing DELLA proteins; however, the extent to which such proteins contribute to GA-mediated fruit development remains to be clarified. Three new plum genes encoding DELLA proteins, PslGAI, Psl...

Subcellular localization of PslDELLA sequences fused to the GFP tag. All constructs were transiently transformed for the assay into N. tabacum protoplasts. NLS-mCherry was included in each transfection to indicate the location of the nucleus. GFP fluorescence is shown as green; the merged image is a digital merge of bright field and fluorescent ima...

Evolutionary relationships of DELLA proteins. The evolutionary distances were computed using the Poisson correction method. The analysis involved 31 amino acid sequences from different plant species that belong to monocots and dicots, including P. salicina (Psl), P. persica (Pp), P. mume (Pm), M. domestica (Md), F. vesca (Fv), V. vinifera (Vv), S....

Alignment of amino acid sequences of the GA-insensitive PslRGAa, PslRGAb (uncharacterized) and their closest GA-sensitive paralog in grape VvDELLA3. Amino acid residues in red represent the three amino acids mutated for functional analysis. Other details as in Fig 1. (DOCX)

Ethylene production and steady-state PslDELLA levels during four different ripening stages [non-climacteric (NC), pre-climacteric (PrC), climacteric (C) and post-climacteric (PoC)] in control EG fruit and fruit pre-treated with propylene (1000 μl l–1) and the ethylene-inhibitor 1-MCP (1 μl l–1). Mature EG fruit (76 DAB) were harvested before autoca...

The oligonucleotide primers. (DOCX)

The 3-D modelling structure of PslGAI, PslRGL, PslRGA, and the Arabidopsis AtGAI proteins. The hydrophobic, polar, positively-, and negatively-charged residues are indicated in white, green, blue and red colors, respectively. (DOCX)

Amino acid sequence comparison between the predicted full-length plum and Arabidopsis DELLA gene family. (DOCX)

Regular consumption of fruit as part of a balanced diet has been associated with health benefits. Bioactive compounds within fruits are the main reason for the increased benefits of consuming them. There has been a growing interest in bioactive substances because of their antioxidant potential and association between their consumption and the preve...

TIR1-like proteins are F-box auxin receptors. Auxin binding to the F-box receptor proteins promotes the formation of SCF TIR1 ubiquitin ligase complex that targets the auxin repressors, Aux/IAAs, for degradation via the ubiquitin/26S proteasome pathway. The release of auxin response factors (ARFs) from their Aux/IAA partners allows ARFs to mediate...

Dutch elm disease (DED), caused by three fungal species in the genus Ophiostoma, is the most devastating disease of both native European and North American elm trees. Although many tolerant cultivars have been identified and released, the tolerance mechanisms are not well understood and true resistance has not yet been achieved. Here we show that t...

Key message: Essential oils have growth regulating properties comparable to the well-documented methyl jasmonate and may be involved in localized and/or airborne plant communication. Aromatic plants employ large amounts of resources to produce essential oils. Some essential oils are known to contain compounds with plant growth regulating activitie...

Regular consumption of fruit as part of a balanced diet has been associated with health benefits. Bioactive compounds within fruits are the main reason for the increased benefits of consuming them. There has been a growing interest in bioactive substances because of their antioxidant potential and association between their consumption and the preve...

Serotonin (5-hydroxytryptamine) is an indoleamine with important physiological functions in plants, including developmental processes and stress responses. In this study, a simple and rapid bioassay was developed to investigate the inhibition of the fruit browning enzyme, polyphenol oxidase (PPO) via serotonin, employing cut apple discs as well as...

Isolation, cloning and molecular characterization of somatic embryogenesis receptor kinase genes (SERK) from plum (Prunus salicina) and peach (Prunus persica) is reported in this paper. Two SERK genes were isolated from peach and one gene was isolated from plum. SERK 1 consisted of 822 bp in Prunus persica and 828 bp in Prunus salicina. The SERK 2...

In order to obtain nutrients from plants for survival and reproduction, phytopathogenic bacteria interfere with and disrupt many plant functions. Interactions between plants and bacteria and their final outcomes are tightly controlled at the molecular level by both organisms. During their coevolution, pathogenic bacteria and plants have evolved var...

Dutch elm disease (DED), caused by ascomycete fungi in the Ophiostoma genus, is the most devastating disease of American elm (Ulmus americana) trees. Cerato ulmin (CU), a hydrophobin secreted by the fungus, has been implicated in the development of DED, but its role in fungal pathogenicity and virulence remains uncertain and controversial. Here, we...

Ethylene has long been considered the key regulator of ripening in climacteric fruit. Recent evidence showed that auxin also plays an important role during fruit ripening, but the nature of the interaction between the two hormones has remained unclear. To understand the differences in ethylene- and auxin-related behaviours that might reveal how the...

European plum fruit (Prunus domestica) are normally blue-black to dark purple. However, some genotypesremain green/yellow after ripening. We hypothesized that in such genotypes anthocyanin biosynthesis is geneticallydisturbed. To examine this hypothesis, six european plum genotypes with diverse fruit colors were investigated for theexpression patte...

Melatonin (N-acetyl-5-methoxytryptamine) has been implicated in abiotic and biotic stress tolerance in plants. However, information on the effects of melatonin in cold stress tolerance in vivo is limited. In this study, the effect of melatonin was investigated in the model plant Arabidopsis thaliana challenged with a cold stress at 4⁰C for 72 and 1...

Fruit growth is a coordinated, complex interaction of cell division, differentiation and expansion. Gibberellin (GA) involvement in the reproductive events is an important aspect of GA effects. Perennial fruit-trees such as plum (Prunus salicina L.) have distinct features that are economically important and provide opportunities to dissect specific...

Key message: Peach ERF3b is a potent transcriptional repressor for defense-related genes even in the presence of similar levels of transcriptional activators and can interfere with plant development through pathways independent of the EAR motif. Ethylene response factors (ERFs) are a major group of plant transcription factors with either activatio...

Key message Peach ERF3b is a potent transcriptional repressor for defense-related genes even in the presence of similar levels of transcriptional activators and can interfere with plant development through pathways independent of the EAR motif. Abstract Ethylene response factors (ERFs) are a major group of plant transcription factors with either...

Auxin-binding protein1 (ABP1) is an active element involved in auxin signaling and plays critical roles in auxin-mediated plant development. Here, we report the isolation and characterization of a putative sequence from Prunus salicina L., designated PslABP1. The expected protein exhibits a similar molecular structure to that of well-characterized...

Ethylene response factors (ERFs) are a large family of transcription factors (TFs) that have diverse functions in plant development and immunity. However, very little is known about the molecular regulation of these TFs in stone fruits during disease incidence. In the present study, we describe the identification of five peach ERFs (Pp-ERFs), aimin...

‘Venture’ and ‘BabyGold 5’ are two peach cultivars with a demonstrated resistance and susceptibility, respectively, to bacterial spot disease caused by Xanthomonas campestris pv. pruni (Xcp). To explore the differences between these cultivars at the molecular level, two PR1 (Pp-PR1a, Pp-PR1b) and three PR5 (Pp-TLP1, Pp-TLP2 and Pp-TLP3) genes were...

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Ginger (Zingiber officinale Roscoe), is an important spice crop that is badly affected by Ralstonia solanacearum wilt. Ginger does not set seed and sexual recombination has never been reported. In spite of extensive search in its habitats, no resistance source to Ralstonia induced bacterial wilt, could be located in ginger. Curcuma amada Roxb. is a...

Ginger (Zingiber officinale Roscoe), is an important spice crop that is badly affected by Ralstonia solanacearum wilt. Ginger does not set seed and sexual recombination has never been reported. In spite of extensive search in its habitats, no resistance source to Ralstonia induced bacterial wilt, could be located in ginger. Curcuma amada Roxb. is a...