Floral scent is a key ornamental trait that determines the quality and commercial value of orchids. Geraniol, an important volatile monoterpene in orchids that attracts pollinators, is also involved ...in responses to stresses but the geraniol synthase (GES) responsible for its synthesis in the medicinal orchid
has not yet been identified. In this study, three potential geraniol synthases were mined from the
genome. DoGES1, which was localized in chloroplasts, was characterized as a geraniol synthase.
was highly expressed in flowers, especially in petals.
transcript levels were high in the budding stage of
flowers at 11:00 a.m. DoGES1 catalyzed geraniol in vitro, and transient expression of
in
leaves resulted in the accumulation of geraniol in vivo. These findings on DoGES1 advance our understanding of geraniol biosynthesis in orchids, and lay the basis for genetic modification of floral scent in
or in other ornamental orchids.
Sandalwood (Santalum album L.) is famous for its unique fragrance derived from the essential oil of heartwood, whose major components are santalols. To understand the mechanism underlying the ...biosynthesis of santalols, in this study, we cloned two related genes involved in the mevalonate pathway in S. album coding for acetyl-CoA C-acetyl transferase (AACT) and 3-hydroxy-3-methyglutary-CoA synthase (HMGS). These genes were characterized and functionally analyzed, and their expression profiles were also assessed. An AACT gene designated as SaAACT (GenBank accession No. MH018694) and a HMGS gene designated as SaHMGS (GenBank accession No. MH018695) were successfully cloned from S. album. The deduced SaAACT and SaHMGS proteins contain 415 and 470 amino acids, and the corresponding size of their open-reading frames is 1538 bp and 1807 bp, respectively. Phylogenetic trees showed that the SaAACT protein had the closest relationship with AACT from Hevea brasiliensis and the SaHMGS proteins had the highest homology with HMGS from Siraitia grosvenorii. Functional complementation of SaAACT and SaHMGS in a mutant yeast strain deficient in these proteins confirmed that SaAACT and SaHMGS cDNA encodes functional SaAACT and SaHMGS that mediate mevalonate biosynthesis in yeast. Tissue-specific expression analysis revealed that both genes were constitutively expressed in all examined tissues (roots, sapwood, heartwood, young leaves, mature leaves and shoots) of S. album, both genes showing highest expression in roots. After S. album seedlings were treated with 100 μM methyl jasmonate, the expression levels of SaAACT and SaHMGS genes increased, suggesting that these genes were responsive to this elicitor. These studies provide insight that would allow further analysis of the role of genes related to the sandalwood mevalonate pathway in the regulation of biosynthesis of sandalwood terpenoids and a deeper understanding of the molecular mechanism of santalol biosynthesis.
Main conclusion
HDA704 enhances drought and salt tolerance via stomata-regulated mechanism. HDA704 negatively regulates stomatal aperture and density, repressing the transcription of DST and ABIL2 by ...histone deacetylation modification.
Drought and salinity can damage crop growth and reduce yield. Stomata play an important role in abiotic stress tolerance. In this study on rice, we identified the RPD3/HDA1-type histone deacetylase HDA704 as a positive regulatory factor in drought and salt tolerance.
HDA704
was induced by drought and salt stresses. Overexpression of
HDA704
in transgenic rice promoted stomatal closure, decreased the number of stomata and slowed down the rate of water loss, consequently resulting in increased drought and salt tolerance. By contrast, knockdown of
HDA704
in transgenic rice decreased stomatal closure and accelerated the rate of water loss, leading to decrease drought and salt tolerance. We detected the transcript expression of
DST
(
Drought and Salt Tolerance
) and
ABIL2
(
Abscisic Acid-insensitive Like2
), which positively regulate stomatal aperture and density in rice. Our results showed that HDA704 directly binds to
DST
and
ABIL2
, repressing their expression via histone deacetylation modification. Collectively, these findings reveal that HDA704 positively regulates drought and salt tolerance by repressing the expression of
DST
and
ABIL2
. Our findings provide a new insight into the molecular mechanisms of stomata-regulated abiotic stress tolerance of plants.
The COVID-19 pandemic, which has led to a flood of papers and preprints, has placed multiple challenges on academic publishing, the most obvious one being sustained integrity under the pressure to ...publish quickly. There are risks of this high volume-to-speed ratio. Many letters, editorials, and supposedly “peer reviewed” papers in ranked and indexed journals were published in a matter of days, suggesting that peer review was either fleeting or non-existential, or that papers were rapidly approved by editors based on their perceived interest and topicality, rather than on their intrinsic academic value. In academic publishing circles, the claim of “peer review”, when in fact it has not been conducted, is a core characteristic of “predatory publishing”, and is also a “fake” element that may undermine efforts in recent years to build trust in science's budding serials crisis. While the world is still centrally focused on COVID-19, the issue of “predatory publishing” is being ignored, or not being given sufficient attention. The risks to the scholarly community, academic publishing and ultimately public health are at stake when exploitative and predatory publishing are left unchallenged.
Abstract
Sandalwood (
Santalum album
L.) is highly valued for its fragrant heartwood and extracted oil. Santalols, which are the main components of that oil, are terpenoids, and these are ...biosynthesized via the mevalonic acid (MVA) pathway. Mevalonate kinase (MK) and phosphomevalonate kinase (PMK) are key enzymes in the MVA pathway. Little is known about the genes that encode MK and PMK in
S. album
or the mechanism that regulates their expression. To isolate and identify the functional genes involved in santalol biosynthesis in
S. album
, an
MK
gene designated as
SaMK
, and a
PMK
gene designated as
SaPMK
, were cloned from
S. album
. The sequences of these genes were analyzed. A bioinformatics analysis was conducted to assess the homology of
SaMK
and
SaPMK
with
MK
and
PMK
genes from other plants. The subcellular localization of
SaMK
and
SaPMK
proteins was also investigated, as was the functional complementation of
SaMK
and
SaPMK
in yeast. Our results show that the full-length cDNA sequences of
SaMK
and
SaPMK
were 1409 bp and 1679 bp long, respectively.
SaMK
contained a 1381 bp open reading frame (ORF) encoding a polypeptide of 460 amino acids and
SaPMK
contained a 1527 bp ORF encoding a polypeptide of 508 amino acids.
SaMK
and
SaPMK
showed high homology with
MK
and
PMK
genes of other plant species. Functional complementation of
SaMK
in a MK-deficient mutant yeast strain YMR208W and
SaPMK
in a PMK-deficient mutant yeast strain YMR220W confirmed that cloned
SaMK
and
SaPMK
cDNA encode a functional MK and PMK, respectively, mediating MVA biosynthesis in yeast. An analysis of tissue expression patterns revealed that
SaMK
and
SaPMK
were constitutively expressed in all the tested tissues.
SaMK
was highly expressed in young leaves but weakly expressed in sapwood.
SaPMK
was highly expressed in roots and mature leaves, but weakly expressed in young leaves. Induction experiments with several elicitors showed that
SaMK
and
SaPMK
expression was upregulated by methyl jasmonate. These results will help to further study the role of
MK
and
PMK
genes during santalol biosynthesis in
S. album
.
Terpene synthase (TPS) is a critical enzyme responsible for the biosynthesis of terpenes, which possess diverse roles in plant growth and development. Although many terpenes have been reported in ...orchids, limited information is available regarding the genome-wide identification and characterization of the TPS family in the orchid,
. By integrating the
genome and transcriptional data, 34
genes were found in
. These were divided into four subfamilies (TPS-a, TPS-b, TPS-c, and TPS-e/f). Distinct tempospatial expression profiles of
genes were observed in 10 organs of
. Most
genes were predominantly expressed in flowers, followed by roots and stems. Expression of the majority of
genes was enhanced following exposure to cold and osmotic stresses. Recombinant DoTPS10 protein, located in chloroplasts, uniquely converted geranyl diphosphate to linalool in vitro. The
gene, which resulted in linalool formation, was highly expressed during all flower developmental stages. Methyl jasmonate significantly up-regulated
expression and linalool accumulation. These results simultaneously provide valuable insight into understanding the roles of the TPS family and lay a basis for further studies on the regulation of terpenoid biosynthesis by
in
.
A recent editorial in
Plant Cell Reports
reaffirms what has been known for years, namely, that it follows the four ICMJE clauses of authorship. That editorial even provides a “perfect” model ...contribution statement. In this letter, I argue that in reality and in practice, authorship delimitations are not that clear-cut, nor are all contributions equal or equally weighted. More importantly, I opine that no matter how eloquently an author contribution statement is written, editors have no way to verify the veracity of those claims. In essence, absent authorship contribution verification, the ICMJE guidelines are practically useless. The responsibility for verification, even to determine authorship associated with papermills or the “ghost” contribution of text by AI like ChatGPT, lies entirely with editors and publishers. Although an unpopular meme, there is need for academic publishing to return to a state of no blind trust.
Apple (Malus × domestica Borkh.; Rosaceae) is an important fruit crop grown mainly in temperate regions of the world. In vitro tissue culture is a biotechnological technique that has been used to ...genetically improve cultivars (scions) and rootstocks. This updated review presents a synthesis of findings related to the tissue culture of apple and other Malus spp. between 2010 and 2018. Increasingly complex molecular studies that are examining the apple genome, for example, in a bid to identify the cause of epigenetic mutations and the role of transposable elements in this process would benefit from genetically stable source material, which can be produced in vitro. Several notable or curious in vitro culture methods have been reported to improve shoot regeneration and induce the production of tetraploids in apple cultivars and rootstocks. Existing studies have revealed the molecular mechanism underlying the inhibition of adventitious roots by cytokinin. The use of the plant growth correction factor allows hypothetical shoot production from leaf-derived thin cell layers relative to conventional leaf explants to be determined. This updated review will allow novices and established researchers to advance apple and Malus biotechnology and breeding programs.
WRKY proteins are a large superfamily of transcription factors that are involved in diverse biological processes including development, as well as biotic and abiotic stress responses in plants. WRKY ...family proteins have been extensively characterized and analyzed in many plant species, including Arabidopsis, rice, and poplar. However, knowledge on WRKY transcription factors in
is scarce. Based on
genome and transcriptome data, 64
genes were identified in this study. A phylogenetic analysis based on the structures of WRKY protein sequences divided these genes into three major groups (I, II, III) together with WRKY protein sequences from Arabidopsis. Tissue-specific expression patterns showed that 37
genes were expressed in at least one of five tissues (leaves, roots, heartwood, sapwood, or the transition zone), while the remaining four genes weakly expressed in all of these tissues. Analysis of the expression profiles of the 42
genes after callus was initiated by salicylic acid (SA) and methyl jasmonate (MeJA) revealed that 25 and 24
genes, respectively, were significantly induced. The function of
, which was significantly up-regulated by SA and MeJA, was analyzed.
was localized in the nucleus and its overexpression improved salt tolerance in transgenic Arabidopsis. Our study provides important information to further identify the functions of
genes and to understand the roles of
family genes involved in the development and in SA- and MeJA-mediated stress responses.
The auxin indole-3-acetic acid (IAA) is a vital phytohormone that influences plant growth and development. Our previous work showed that IAA content decreased during flower development in the ...medicinally important orchid Dendrobium officinale, while Aux/IAA genes were downregulated. However, little information about auxin-responsive genes and their roles in D. officinale flower development exists.
This study validated 14 DoIAA and 26 DoARF early auxin-responsive genes in the D. officinale genome. A phylogenetic analysis classified the DoIAA genes into two subgroups. An analysis of cis-regulatory elements indicated that they were related by phytohormones and abiotic stresses. Gene expression profiles were tissue-specific. Most DoIAA genes (except for DoIAA7) were sensitive to IAA (10 μmol/L) and were downregulated during flower development. Four DoIAA proteins (DoIAA1, DoIAA6, DoIAA10 and DoIAA13) were mainly localized in the nucleus. A yeast two-hybrid assay showed that these four DoIAA proteins interacted with three DoARF proteins (DoARF2, DoARF17, DoARF23).
The structure and molecular functions of early auxin-responsive genes in D. officinale were investigated. The DoIAA-DoARF interaction may play an important role in flower development via the auxin signaling pathway.
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