Tomato (
) breeding for improved fruit quality emphasizes selecting for desirable taste and characteristics, as well as enhancing disease resistance and yield. Seed germination is the initial step in ...the plant life cycle and directly affects crop productivity and yield. ERECTA (ER) is a receptor-like kinase (RLK) family protein known for its involvement in diverse developmental processes. We characterized a Micro-Tom EMS mutant designated as a knock-out mutant of
. Our research reveals that
plays a central role in controlling critical traits such as inflorescence development, seed number, and seed germination. The elevation in auxin levels and alterations in the expression of
(
) and
in
seeds compared to the WT indicate that
modulates seed germination via auxin and abscisic acid (ABA) signaling. Additionally, we detected an increase in auxin content in the
ovary and changes in the expression of auxin synthesis genes
(
),
,
, and
as well as auxin response genes
(
) and
, suggesting that
regulates fruit development via auxin signaling.
Heterosis contributes greatly to the worldwide agricultural yield. However, the molecular mechanism underlying heterosis remains unclear. This study took advantage of Arabidopsis intraspecific ...hybrids to identify heterosis-related metabolites. Forty-six intraspecific hybrids were used to examine parental effects on seed area and germination time. The degree of heterosis was evaluated based on biomass: combinations showing high heterosis of F
hybrids exhibited a biomass increase from 6.1 to 44% over the better parent value (BPV), whereas that of the low- and no-heterosis hybrids ranged from - 19.8 to 9.8% over the BPV. Metabolomics analyses of F
hybrids with high heterosis and those with low one suggested that changes in TCA cycle intermediates are key factors that control growth. Notably, higher fumarate/malate ratios were observed in the high heterosis F
hybrids, suggesting they provide metabolic support associated with the increased biomass. These hybrids may produce more energy-intensive biomass by speeding up the efficiency of TCA fluxes. However, the expression levels of TCA-process-related genes in F
hybrids were not associated with the intensity of heterosis, suggesting that the post-transcriptional or post-translational regulation of these genes may affect the productivity of the intermediates in the TCA cycle.
Our meta-epidemiological study aimed to describe the prevalence of reporting effect modification only on relative scale outcomes and inappropriate interpretations of the coefficient of interaction ...terms in nonlinear models on categorical outcomes. Our study targeted articles published in the top 10 high-impact-factor journals between 1 January and 31 December 2021. We included two-arm, parallel-group, interventional superiority randomized controlled trials to evaluate the effects of modifications on categorical outcomes. The primary outcomes were the prevalence of reporting effect modifications only on relative scale outcomes and that of inappropriately interpreting the coefficient of interaction terms in nonlinear models on categorical outcomes. We included 52 articles, of which 41 (79%) used nonlinear regression to evaluate effect modifications. At least 45/52 articles (87%) reported effect modifications based only on relative scale outcomes, and at least 39/41 (95%) articles inappropriately interpreted the coefficient of interaction terms merely as indices of effect modifications. The quality of the evaluations of effect modifications in nonlinear models on categorical outcomes was relatively low, even in randomized controlled trials published in medical journals with high impact factors. Researchers should report effect modifications of both absolute and relative scale outcomes and avoid interpreting the coefficient of interaction terms in nonlinear regression analyses.
A diploid organism has two copies of each gene, one inherited from each parent. The expression of two inherited alleles is sometimes biased by the effects known as dominant/recessive relationships, ...which determine the final phenotype of the organism. To explore the mechanisms underlying these relationships, we have examined the monoallelic expression of S-locus protein 11 genes (SP11), which encode the male determinants of self-incompatibility in Brassica. We previously reported that SP11 expression was monoallelic in some S heterozygotes, and that the promoter regions of recessive SP11 alleles were specifically methylated in the anther tapetum. Here we show that this methylation is controlled by trans-acting small non-coding RNA (sRNA). We identified inverted genomic sequences that were similar to the recessive SP11 promoters in the flanking regions of dominant SP11 alleles. These sequences were specifically expressed in the anther tapetum and processed into 24-nucleotide sRNA, named SP11 methylation inducer (Smi). Introduction of the Smi genomic region into the recessive S homozygotes triggered the methylation of the promoter of recessive SP11 alleles and repressed their transcription. This is an example showing sRNA encoded in the flanking region of a dominant allele acts in trans to induce transcriptional silencing of the recessive allele. Our finding may provide new insights into the widespread monoallelic gene expression systems.
Heterosis refers to the improved agronomic performance of F1 hybrids relative to their parents. Although this phenomenon is widely employed to increase biomass, yield, and stress tolerance of plants, ...the underlying molecular mechanisms remain unclear. To dissect the metabolic fluctuations derived from genomic and/or environmental differences contributing to the improved biomass of F1 hybrids relative to their parents, we optimized the growth condition for Arabidopsis thaliana F1 hybrids and their parents. Modest but statistically significant increase in the biomass of F1 hybrids was observed. Plant samples grown under the optimized condition were also utilized for integrated omics analysis to capture specific changes in the F1 hybrids. Metabolite profiling of F1 hybrids and parent plants was performed using gas chromatography-mass spectrometry. Among the detected 237 metabolites, 2-oxoglutarate (2-OG) and malate levels were lower and the level of aspartate was higher in the F1 hybrids than in each parent. In addition, microarray analysis revealed that there were 44 up-regulated and 12 down-regulated genes with more than 1.5-fold changes in expression levels in the F1 hybrid compared to each parent. Gene ontology (GO) analyses indicated that genes up-regulated in the F1 hybrids were largely related to organic nitrogen (N) process. Quantitative PCR verified that glutamine synthetase 2 (AtGLN2) was upregulated in the F1 hybrids, while other genes encoding enzymes in the GS-GOGAT cycle showed no significant differences between the hybrid and parent lines. These results suggested the existence of metabolic regulation that coordinates biomass and N metabolism involving AtGLN2 in F1 hybrids.
Pollen tube growth is crucial for the delivery of sperm cells to the ovule during flowering plant reproduction. Previous in vitro imaging of Lilium longiflorum and Nicotiana tabacum has shown that ...growing pollen tubes exhibit a tip-focused Ca²⁺ concentration (Ca²⁺) gradient and regular oscillations of the cytosolic Ca²⁺ (Ca²⁺cyt) in the tip region. Whether this Ca²⁺ gradient and/or Ca²⁺cyt oscillations are present as the tube grows through the stigma (in vivo condition), however, is still not clear. We monitored Ca²⁺cyt dynamics in pollen tubes under various conditions using Arabidopsis (Arabidopsis thaliana) and N. tabacum expressing yellow cameleon 3.60, a fluorescent calcium indicator with a large dynamic range. The tip-focused Ca²⁺cyt gradient was always observed in growing pollen tubes. Regular oscillations of the Ca²⁺cyt, however, were rarely identified in Arabidopsis or N. tabacum pollen tubes grown under the in vivo condition or in those placed in germination medium just after they had grown through a style (semi-in vivo condition). On the other hand, regular oscillations were observed in vitro in both growing and nongrowing pollen tubes, although the oscillation amplitude was 5-fold greater in the nongrowing pollen tubes compared with growing pollen tubes. These results suggested that a submicromolar Ca²⁺cyt in the tip region is essential for pollen tube growth, whereas a regular Ca²⁺ oscillation is not. Next, we monitored Ca²⁺ dynamics in the endoplasmic reticulum (Ca²⁺ER) in relation to Arabidopsis pollen tube growth using yellow cameleon 4.60, which has a lower affinity for Ca²⁺ compared with yellow cameleon 3.60. The Ca²⁺ER in pollen tubes grown under the semi-in vivo condition was between 100 and 500 μM. In addition, cyclopiazonic acid, an inhibitor of ER-type Ca²⁺-ATPases, inhibited growth and decreased the Ca²⁺ER. Our observations suggest that the ER serves as one of the Ca²⁺ stores in the pollen tube and cyclopiazonic acid-sensitive Ca²⁺-ATPases in the ER are required for pollen tube growth.
Spermatogenesis associated 4 (Spata4), a testis-specific and CpG island associated gene, is involved in regulating cell proliferation, differentiation and apoptosis. To obtain insight into the role ...of Spata4 in cell cycling control, we characterized the promoter region of Spata4 and investigated its transcriptional regulation mechanism. The Spata4 promoter is unidirectional transcribed and possesses multiple transcription start sites. Moreover, we present evidence that regulatory factor X1 (RFX1) could bind the typical 14-bp cis-elements of Spata4 promoter, modulate transcriptional activity and endogenous expression of Spata4, and further regulate the proliferation of Sertoli cells. Overexpression of RFX1 was shown to down-regulate both the promoter activity and mRNA expression of Spata4, whereas knockdown of RFX1 demonstrated the opposite effects. Our studies provide insight into Spata4 gene regulation and imply the potential role of RFX1 in growth of Sertoli cells. RFX1 may have negative effect on cell proliferation of Sertoli cells via modulating Spata4 expression levels by binding the conserved 14-bp cis-elements of Spata4 promoter.
Many higher plants have evolved self-incompatibility mechanisms to prevent self-fertilization. In Brassica self-incompatibility, recognition between pollen and the stigma is controlled by the S ...locus, which contains three highly polymorphic genes: S-receptor kinase (SRK), S-locus protein 11 (SP11) (also called S-locus cysteine-rich protein; SCR) and S-locus glycoprotein (SLG). SRK encodes a membrane-spanning serine/threonine kinase that determines the S-haplotype specificity of the stigma, and SP11 encodes a small cysteine-rich protein that determines the S-haplotype specificity of pollen. SP11 is localized in the pollen coat. It is thought that, during self-pollination, SP11 is secreted from the pollen coat and interacts with its cognate SRK in the papilla cell of the stigma to elicit the self-incompatibility response. SLG is a secreted stigma protein that is highly homologous to the SRK extracellular domain. Although it is not required for S-haplotype specificity of the stigma, SLG enhances the self-incompatibility response; however, how this is accomplished remains controversial. Here we show that a single form of SP11 of the S8 haplotype (S8-SP11) stabilized with four intramolecular disulphide bonds specifically binds the stigma membrane of the S8 haplotype to induce autophosphorylation of SRK8, and that SRK8 and SLG8 together form a high-affinity receptor complex for S8-SP11 on the stigma membrane.
Hayata is a small-fruit citrus species; it is indigenous to Kagoshima, Okinawa, and Taiwan. The metabolites and volatile organic compounds (VOCs) that affect the flavor of its fruits have not been ...investigated based on geographical origin. In the present study, we investigated the metabolite and VOC profiles of 18
cultivation lines from these regions. Multivariate analysis revealed differences in the metabolites of
based on its cultivation origins; variations in sugar, sugar alcohol, and amino acid contents were also observed. Fruits from Kagoshima and Okinawa had higher galactinol, trehalose, xylose, glucose, and sucrose intensities than fruits from Taiwan (log
-fold change; 2.65-3.44, 1.68-2.13, 1.37-2.01, 1.33-1.57, and 1.07-1.43, respectively), whereas the Taiwanese lines contained higher leucine, isoleucine, serine, and alanine. In contrast to the Taiwanese Nantou line, other cultivation lines had comparable total VOC contents, and the VOCs of all lines were dominated by limonene,
-terpinene, and
-cymene. Accordingly, the highest VOC intensities were recorded in the Nantou line, which was followed by Shikunin sweet (Kagoshima) and Taoyuan (Taiwan) (log
normalize concentration; 5.11, 3.08, and 3.01, respectively). Moreover, multivariate analysis plots elucidated the difference in the VOCs of Ishikunibu (Okinawa), Shikunin sweet, and Taoyuan and between those of most Kagoshima and Okinawa cultivation lines. These results suggest that both the cultivation line and origin influence the metabolites and VOCs of
, thus possibly affecting its flavor quality; the data provide a valuable insight for utilizing
of different cultivation lines and origins to produce foods and beverages.
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