Natural polymorphisms in ZMET2 encoding a DNA methyltransferase modulate the number of husk layers in maize.

DNA methylation affects agronomic traits and the environmental adaptability of crops, but the natural polymorphisms in DNA methylation-related genes and their contributions to phenotypic variation in maize (Zea mays) remain elusive. Here, we show that a polymorphic 10-bp insertion/deletion variant in the 3'UTR of Zea methyltransferase2 (ZMET2) alters its transcript level and accounts for variation in the number of maize husk layers. ZMET2 encodes a chromomethylase and is required for maintaining genome-wide DNA methylation in the CHG sequence context. Disruption of ZMET2 increased the number of husk layers and resulted in thousands of differentially methylated regions, a proportion of which were also distinguishable in natural ZMET2 alleles. Population genetic analyses indicated that ZMET2 was a target of selection and might play a role in the spread of maize from tropical to temperate regions. Our results provide important insights into the natural variation of ZMET2 that confers both global and locus-specific effects on DNA methylation, which contribute to phenotypic diversity in maize.

Genetic analysis of QTLs for lysine content in four maize DH populations.

BACKGROUND: Low levels of the essential amino acid lysine in maize endosperm is considered to be a major problem regarding the nutritional quality of food and feed. Increasing the lysine content of maize is important to improve the quality of food and feed nutrition. Although the genetic basis of quality protein maize (QPM) has been studied, the further exploration of the quantitative trait loci (QTL) underlying lysine content variation still needs more attention. RESULTS: Eight maize inbred lines with increased lysine content were used to construct four double haploid (DH) populations for identification of QTLs related to lysine content. The lysine content in the four DH populations exhibited continuous and normal distribution. A total of 12 QTLs were identified in a range of 4.42-12.66% in term of individual phenotypic variation explained (PVE) which suggested the quantitative control of lysine content in maize. Five main genes involved in maize lysine biosynthesis pathways in the QTL regions were identified in this study. CONCLUSIONS: The information presented will allow the exploration of candidate genes regulating lysine biosynthesis pathways and be useful for marker-assisted selection and gene pyramiding in high-lysine maize breeding programs.

The RHW1-ZCN4 regulatory pathway confers natural variation of husk leaf width in maize.

Maize husk leaf - the outer leafy layers covering the ear - modulates kernel yield and quality. Despite its importance, however, the genetic controls underlying husk leaf development remain elusive. Our previous genome-wide association study identified a single nucleotide polymorphism located in the gene RHW1 (Regulator of Husk leaf Width) that is significantly associated with husk leaf-width diversity in maize. Here, we further demonstrate that a polymorphic 18-bp InDel (insertion/deletion) variant in the 3' untranslated region of RHW1 alters its protein abundance and accounts for husk leaf width variation. RHW1 encodes a putative MYB-like transcriptional repressor. Disruption of RHW1 altered cell proliferation and resulted in a narrower husk leaf, whereas RHW1 overexpression yielded a wider husk leaf. RHW1 positively regulated the expression of ZCN4, a well-known TFL1-like protein involved in maize ear development. Dysfunction of ZCN4 reduced husk leaf width even in the context of RHW1 overexpression. The InDel variant in RHW1 is subject to selection and is associated with maize husk leaf adaption from tropical to temperate regions. Overall, our results identify that RHW1-ZCN4 regulates a pathway conferring husk leaf width variation at a very early stage of husk leaf development in maize.

MMAP: a cloud computing platform for mining the maximum accuracy of predicting phenotypes from genotypes.

Accurately predicting phenotypes from genotypes holds great promise to improve health management in humans and animals, and breeding efficiency in animals and plants. Although many prediction methods have been developed, the optimal method differs across datasets due to multiple factors, including species, environments, populations and traits of interest. Studies have demonstrated that the number of genes underlying a trait and its heritability are the two key factors that determine which method fits the trait the best. In many cases, however, these two factors are unknown for the traits of interest. We developed a cloud computing platform for Mining the Maximum Accuracy of Predicting phenotypes from genotypes (MMAP) using unsupervised learning on publicly available real data and simulated data. MMAP provides a user interface to upload input data, manage projects and analyses and download the output results. The platform is free for the public to conduct computations for predicting phenotypes and genetic merit using the best prediction method optimized from many available ones, including Ridge Regression, gBLUP, compressed BLUP, Bayesian LASSO, Bayes A, B, Cpi and many more. Users can also use the platform to conduct data analyses with any methods of their choice. It is expected that extensive usage of MMAP would enrich the training data, which in turn results in continual improvement of the identification of the best method for use with particular traits. AVAILABILITY AND IMPLEMENTATION: The MMAP user manual, tutorials and example datasets are available at http://zzlab.net/MMAP. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

The association of obesity with the progression and outcome of COVID-19: The insight from an artificial-intelligence-based imaging quantitative analysis on computed tomography.

AIMS: To explore the association of obesity with the progression and outcome of coronavirus disease 2019 (COVID-19) at the acute period and 5-month follow-up from the perspectives of computed tomography (CT) imaging with artificial intelligence (AI)-based quantitative evaluation, which may help to predict the risk of obese COVID-19 patients progressing to severe and critical disease. MATERIALS AND METHODS: This retrospective cohort enrolled 213 hospitalized COVID-19 patients. Patients were classified into three groups according to their body mass index (BMI): normal weight (from 18.5 to <24 kg/m2 ), overweight (from 24 to <28 kg/m2 ) and obesity (≥28 kg/m2 ). RESULTS: Compared with normal-weight patients, patients with higher BMI were associated with more lung involvements in lung CT examination (lung lesions volume [cm3 ], normal weight vs. overweight vs. obesity; 175.5[34.0-414.9] vs. 261.7[73.3-576.2] vs. 395.8[101.6-1135.6]; p = 0.002), and were more inclined to deterioration at the acute period. At the 5-month follow-up, the lung residual lesion was more serious (residual total lung lesions volume [cm3 ], normal weight vs. overweight vs. obesity; 4.8[0.0-27.4] vs. 10.7[0.0-55.5] vs. 30.1[9.5-91.1]; p = 0.015), and the absorption rates were lower for higher BMI patients (absorption rates of total lung lesions volume [%], normal weight vs. overweight vs. obesity; 99.6[94.0-100.0] vs. 98.9[85.2-100.0] vs. 88.5[66.5-95.2]; p = 0.013). The clinical-plus-AI parameter model was superior to the clinical-only parameter model in the prediction of disease deterioration (areas under the ROC curve, 0.884 vs. 0.794, p < 0.05). CONCLUSIONS: Obesity was associated with severe pneumonia lesions on CT and adverse clinical outcomes. The AI-based model with combinational use of clinical and CT parameters had incremental prognostic value over the clinical parameters alone.

Diagnosis and genetic analysis of a case of Waardenburg syndrome type 2 with hypogonadotropic hypogonadism caused by SOX10 gene deletion.

Hypogonadotropic hypogonadism (HH) is a disease defined by dysfunction of the hypothalamic- pituitary-gonadal hormone axis, leading to low sex hormone levels and impaired fertility. HH with anosmia or hyposmia is known as Kallmann syndrome (KS). Waardenburg syndrome (WS) is a rare autosomal dominant genetic disorder characterized by sensorineural hearing loss and abnormal pigmentation. In this report, we collected the clinical data of a patient with hypogonadotropic hypogonadism and congenital hearing loss of unknown cause. The patient had no obvious secondary sexual characteristics development after puberty, and had a heterozygous deletion (at least 419 kb) in 22q13.1 region (Chr.22:38106433-38525560), which covered the SOX10 gene. The abnormalities were not found in gene sequencing analysis of both the parents and sister of the proband. By summarizing and analyzing the characteristics of this case, we further discussed the molecular biological etiological association between HH and WS type 2. This case also enriches the clinical data of subsequent genetic studies, and provides a reference for the diagnosis and treatment of such diseases.

Genetic analysis of three maize husk traits by QTL mapping in a maize-teosinte population.

BACKGROUND: The maize husk consists of numerous leafy layers and plays vital roles in protecting the ear from pathogen infection and dehydration. Teosinte, the wild ancestor of maize, has about three layers of small husk outer covering the ear. Although several quantitative trait loci (QTL) underlying husk morphology variation have been reported, the genetic basis of husk traits between teosinte and maize remains unclear. RESULTS: A linkage population including 191 BC2F8 inbred lines generated from the maize line Mo17 and the teosinte line X26-4 was used to identify QTL associated with three husk traits: i.e., husk length (HL), husk width (HW) and the number of husk layers (HN). The best linear unbiased predictor (BLUP) depicted wide phenotypic variation and high heritability of all three traits. The HL exhibited greater correlation with HW than HN. A total of 4 QTLs were identified including 1, 1, 2, which are associated with HL, HW and HN, respectively. The proportion of phenotypic variation explained by these QTLs was 9.6, 8.9 and 8.1% for HL, HN and HW, respectively. CONCLUSIONS: The QTLs identified in this study will pave a path to explore candidate genes regulating husk growth and development, and benefit the molecular breeding program based on molecular marker-assisted selection to cultivate maize varieties with an ideal husk morphology.

Suppression of the hypothalamic-pituitary-thyroid axis is associated with the severity of prognosis in hospitalized patients with COVID-19.

BACKGROUND: The outbreak of severe acute respiratory syndrome novel coronavirus 2 (SARS-CoV-2) has spread rapidly worldwide. SARS-CoV-2 has been found to cause multiple organ damage; however, little attention has been paid to the damage to the endocrine system caused by this virus, and the subsequent impact on prognosis. This may be the first research on the hypothalamic-pituitary-thyroid (HPT) axis and prognosis in coronavirus disease 2019 (COVID-19). METHODS: In this retrospective observational study, 235 patients were admitted to the hospital with laboratory-confirmed SARS-CoV-2 infection from 22 January to 17 March 2020. Clinical characteristics, laboratory findings, and treatments were obtained from electronic medical records with standard data collection forms and compared among patients with different thyroid function status. RESULTS: Among 235 patients, 17 (7.23%) had subclinical hypothyroidism, 11 (4.68%) severe non-thyroidal illness syndrome (NTIS), and 23 (9.79%) mild to moderate NTIS. Composite endpoint events of each group, including mortality, admission to the ICU, and using IMV were observed. Compared with normal thyroid function, the hazard ratios (HRs) of composite endpoint events for mild to moderate NTIS, severe NTIS, subclinical hypothyroidism were 27.3 (95% confidence interval [CI] 7.07-105.7), 23.1 (95% CI 5.75-92.8), and 4.04 (95% CI 0.69-23.8) respectively. The multivariate-adjusted HRs for acute cardiac injury among patients with NTF, subclinical hypothyroidism, severe NTIS, and mild to moderate NTIS were 1.00, 1.68 (95% CI 0.56-5.05), 4.68 (95% CI 1.76-12.4), and 2.63 (95% CI 1.09-6.36) respectively. CONCLUSIONS: Our study shows that the suppression of the HPT axis could be a common complication in COVID-19 patients and an indicator of the severity of prognosis. Among the three different types of thyroid dysfunction with COVID-19, mild to moderate NTIS and severe NTIS have a higher risk of severe outcomes compared with subclinical hypothyroidism.

Characterization of ZmCOLD1, novel GPCR-Type G Protein genes involved in cold stress from Zea mays L. and the evolution analysis with those from other species.

Maize is one of the most vital staple crops worldwide. G proteins modulate plentiful signaling pathways, and G protein-coupled receptor-type G proteins (GPCRs) are highly conserved membrane proteins in plants. However, researches on maize G proteins and GPCRs are scarce. In this study, we identified three novel GPCR-Type G Protein (GTG) genes from chromosome 10 (Chr 10) in maize, designated as ZmCOLD1-10A, ZmCOLD1-10B and ZmCOLD1-10C. Their amino acid sequences had high similarity to TaCOLD1 from wheat and OsCOLD1 from rice. They contained the basic characteristics of GTG/COLD1 proteins, including GPCR-like topology, the conserved hydrophilic loop (HL) domain, DUF3735 (domain of unknown function 3735) domain, GTPase-activating domain, and ATP/GTP-binding domain. Subcellular localization analyses of ZmCOLD1 proteins suggested that ZmCOLD1 proteins localized on plasma membrane (PM) and endoplasmic reticulum (ER). Furthermore, amino acid sequence alignment verified the conservation of the key 187th amino acid T in maize and other wild maize-relative species. Evolutionary relationship among plants GTG/COLD1 proteins family displayed strong group-specificity. Expression analysis indicated that ZmCOLD1-10A was cold-induced and inhibited by light. Together, these results suggested that ZmCOLD1 genes had potential value to improve cold tolerance and to contribute crops growth and molecular breeding.

Newly diagnosed diabetes is associated with a higher risk of mortality than known diabetes in hospitalized patients with COVID-19.

AIM: To evaluate the association between different degrees of hyperglycaemia and the risk of all-cause mortality among hospitalized patients with COVID-19. MATERIALS AND METHODS: In a retrospective study conducted from 22 January to 17 March 2020, 453 patients were admitted to Union Hospital in Wuhan, China, with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection. Patients were classified into four categories: normal glucose, hyperglycaemia (fasting glucose 5.6-6.9 mmol/L and/or HbA1c 5.7%-6.4%), newly diagnosed diabetes (fasting glucose ≥7 mmol/L and/or HbA1c ≥6.5%) and known diabetes. The major outcomes included in-hospital mortality, intensive care unit (ICU) admission and invasive mechanical ventilation (IMV). RESULTS: Patients with newly diagnosed diabetes constituted the highest percentage to be admitted to the ICU (11.7%) and require IMV (11.7%), followed by patients with known diabetes (4.1%; 9.2%) and patients with hyperglycaemia (6.2%; 4.7%), compared with patients with normal glucose (1.5%; 2.3%), respectively. The multivariable-adjusted hazard ratios of mortality among COVID-19 patients with normal glucose, hyperglycaemia, newly diagnosed diabetes and known diabetes were 1.00, 3.29 (95% confidence interval [CI] 0.65-16.6), 9.42 (95% CI 2.18-40.7) and 4.63 (95% CI 1.02-21.0), respectively. CONCLUSION: We showed that COVID-19 patients with newly diagnosed diabetes had the highest risk of all-cause mortality compared with COVID-19 patients with known diabetes, hyperglycaemia and normal glucose. Patients with COVID-19 need to be kept under surveillance for blood glucose screening.

ZmRAD51C is Essential for Double-Strand Break Repair and Homologous Recombination in Maize Meiosis.

Radiation sensitive 51 (RAD51) recombinases play crucial roles in meiotic double-strand break (DSB) repair mediated by homologous recombination (HR) to ensure the correct segregation of homologous chromosomes. In this study, we identified the meiotic functions of ZmRAD51C, the maize homolog of Arabidopsis and rice RAD51C. The Zmrad51c mutants exhibited regular vegetative growth but complete sterility for both male and female inflorescence. However, the mutants showed hypersensitivity to DNA damage by mitomycin C. Cytological analysis indicated that homologous chromosome pairing and synapsis were rigorously inhibited, and meiotic chromosomes were often entangled from diplotene to metaphase I, leading to chromosome fragmentation at anaphase I. Immunofluorescence analysis showed that although the signals of the axial element absence of first division (AFD1) and asynaptic1 (ASY1) were normal, the assembly of the central element zipper1 (ZYP1) was severely disrupted. The DSB formation was normal in Zmrad51c meiocytes, symbolized by the regular occurrence of γH2AX signals. However, RAD51 and disrupted meiotic cDNA 1 (DMC1) signals were never detected at the early stage of prophase I in the mutant. Taken together, our results indicate that ZmRAD51C functions crucially for both meiotic DSB repair and homologous recombination in maize.

ATX3, ATX4, and ATX5 Encode Putative H3K4 Methyltransferases and Are Critical for Plant Development.

Methylation of Lys residues in the tail of the H3 histone is a key regulator of chromatin state and gene expression, conferred by a large family of enzymes containing an evolutionarily conserved SET domain. One of the main types of SET domain proteins are those controlling H3K4 di- and trimethylation. The genome of Arabidopsis (Arabidopsis thaliana) encodes 12 such proteins, including five ARABIDOPSIS TRITHORAX (ATX) proteins and seven ATX-Related proteins. Here, we examined three until-now-unexplored ATX proteins, ATX3, ATX4, and ATX5. We found that they exhibit similar domain structures and expression patterns and are redundantly required for vegetative and reproductive development. Concurrent disruption of the ATX3, ATX4, and ATX5 genes caused marked reduction in H3K4me2 and H3K4me3 levels genome-wide and resulted in thousands of genes expressed ectopically. Furthermore, atx3/atx4/atx5 triple mutants resulted in exaggerated phenotypes when combined with the atx2 mutant but not with atx1 Together, we conclude that ATX3, ATX4, and ATX5 are redundantly required for H3K4 di- and trimethylation at thousands of sites located across the genome, and genomic features associated with targeted regions are different from the ATXR3/SDG2-controlled sites in Arabidopsis.

Linkage mapping combined with association analysis reveals QTL and candidate genes for three husk traits in maize.

Key message Combined linkage and association mapping analyses facilitate the emphasis on the candidate genes putatively involved in maize husk growth. The maize (Zea mays L.) husk consists of multiple leafy layers and plays important roles in protecting the ear from pathogen infection and in preventing grain dehydration. Although husk morphology varies widely among different maize inbred lines, the genetic basis of such variation is poorly understood. In this study, we used three maize recombinant inbred line (RIL) populations to dissect the genetic basis of three husk traits: i.e., husk length (HL), husk width (HW), and the number of husk layers (HN). Three husk traits in all three RIL populations showed wide phenotypic variation and high heritability. The HL showed stronger correlations with ear traits than did HW and HN. A total of 21 quantitative trait loci (QTL) were identified for the three traits in three RIL populations, and some of them were commonly observed for the same trait in different populations. The proportions of total phenotypic variation explained by QTL in three RIL populations were 31.8, 35.3, and 44.5% for HL, HW, and HN, respectively. The highest proportions of phenotypic variation explained by a single QTL were 14.7% for HL in the By815/K22 RIL population (BYK), 13.5% for HW in the By815/DE3 RIL population (BYD), and 19.4% for HN in the BYD population. A combined analysis of linkage mapping with a previous genome-wide association study revealed five candidate genes related to husk morphology situated within three QTL loci. These five genes were related to metabolism, gene expression regulation, and signal transduction.

Genome-wide association study (GWAS) reveals the genetic architecture of four husk traits in maize.

BACKGROUND: Maize (Zea mays) husk referring to the leafy outer enclosing the ear, plays an important role in grain production by directly contributing photosynthate and protecting ear from pathogen infection. Although the physiological functions related to husk have been extensively studied, little is known about its morphological variation and genetic basis in natural population. RESULTS: Here we utilized a maize association panel including 508 inbred lines with tropical, subtropical and temperate backgrounds to decipher the genetic architecture attributed to four husk traits, i.e. number of layers, length, width and thickness. Evaluating the phenotypic diversity at two different environments showed that four traits exhibit broadly natural variations and moderate levels of heritability with 0.64, 0.74, 0.49 and 0.75 for number, length, width and thickness, respectively. Diversity analysis indicated that different traits have dissimilar responses to subpopulation effects. A series of significantly positive or negative correlations between husk phenotypes and other agronomic traits were identified, indicating that husk growth is coordinated with other developmental processes. Combining husk traits with about half of a million of single nucleotide polymorphisms (SNPs) via genome-wide association study revealed a total of 9 variants significantly associated with traits at P < 1.04 × 10-5, which are implicated in multiple functional categories, such as cellular trafficking, transcriptional regulation and metabolism. CONCLUSIONS: These results provide instrumental information for understanding the genetic basis of husk development, and further studies on identified candidate genes facilitate to illuminate molecular pathways regulating maize husk growth.

Dissipation of excess excitation energy of the needle leaves in Pinus trees during cold winters.

Photooxidative damage to the needle leaves of evergreen trees results from the absorption of excess excitation energy. Efficient dissipation of this energy is essential to prevent photodamage. In this study, we determined the fluorescence transients, absorption spectra, chlorophyll contents, chlorophyll a/b ratios, and relative membrane permeabilities of needle leaves of Pinus koraiensis, Pinus tabulaeformis, and Pinus armandi in both cold winter and summer. We observed a dramatic decrease in the maximum fluorescence (F m) and substantial absorption of light energy in winter leaves of all three species. The F m decline was not correlated with a decrease in light absorption or with changes in chlorophyll content and chlorophyll a/b ratio. The results suggested that the winter leaves dissipated a large amount of excess energy as heat. Because the cold winter leaves had lost normal physiological function, the heat dissipation depended solely on changes in the photosystem II supercomplex rather than the xanthophyll cycle. These findings imply that more attention should be paid to heat dissipation via changes in the photosystem complex structure during the growing season.

Sucrose Transporter AtSUC9 Mediated by a Low Sucrose Level is Involved in Arabidopsis Abiotic Stress Resistance by Regulating Sucrose Distribution and ABA Accumulation.

Sucrose (Suc) transporters (SUCs or SUTs) are important regulators in plant growth and stress tolerance. However, the mechanism of SUCs in plant abiotic stress resistance remains to be dietermined. Here, we found that AtSUC9 expression was induced by abiotic stress, including salt, osmotic and cold stress conditions. Disruption of AtSUC9 led to sensitive responses to abiotic stress during seed germination and seedling growth. Further analyses indicated that the sensitivity phenotype of Atsuc9 mutants resulted from higher Suc content in shoots and lower Suc content in roots, as compared with that in wild-type (WT) plants. In addition, we found that the expression of AtSUC9 is induced in particular by low levels of exogenous and endogenous Suc, and deletion of AtSUC9 affected the expression of the low Suc level-responsive genes. AtSUC9 also showed an obvious response to treatments with low concentrations of exogenous Suc during seed germination, seedling growth and Suc distribution, and Atsuc9 mutants hardly grew in abiotic stress treatments without exogenous Suc. Moreover, our results illustrated not only that deletion of AtSUC9 blocks abiotic stress-inducible ABA accumulation but also that Atsuc9 mutants had a lower content of endogenous ABA in stress conditions than in normal conditions. Deletion of AtSUC9 also inhibited the expression of many ABA-inducible genes (SnRk2.2/3/6, ABF2/3/4, ABI1/3/4, RD29A, KIN1 and KIN2). These results indicate that AtSUC9 is induced in particular by low Suc levels then mediates the balance of Suc distribution and promotes ABA accumulation to enhance Arabidopsis abiotic stress resistance.

Introduction of two mutations into AroG increases phenylalanine production in Escherichia coli.

L-Phenylalanine is an important amino acid commercially, and therefore optimization of its manufacture is of interest. We constructed a range of mutant alleles of AroG, the enzyme involved in the first step of phenylalanine biosynthesis. Three single-site mutant alleles were constructed (aroG8, aroG15, and aroG29), which were then combined to generate three double-site aroG (fbr) mutant alleles (aroG8/15, aroG8/29, and aroG15/29). Enzymatic activity, feedback inhibition, and fermentation were analyzed in all of the mutants. All double-site mutants, except AroG15/29, showed higher enzymatic activity and greater resistance to feedback inhibition than their respective single-site mutants. The E. coli strain carrying the aroG8/15 allele produced a phenylalanine titer of 26.78 g/l, a 116 % improvement over the control phenylalanine overproducing strain (12.41 g/l). Our findings provide an effective method for modifying phenylalanine biosynthetic genes, which may be applied to optimize the commercial manufacture of phenylalanine.

Genomic selection to improve husk tightness based on genomic molecular markers in maize.

Introduction: The husk tightness (HTI) in maize plays a crucial role in regulating the water content of ears during the maturity stage, thereby influencing the quality of mechanical grain harvesting in China. Genomic selection (GS), which employs molecular markers, offers a promising approach for identifying and selecting inbred lines with the desired HTI trait in maize breeding. However, the effectiveness of GS is contingent upon various factors, including the genetic architecture of breeding populations, sequencing platforms, and statistical models. Methods: An association panel of maize inbred lines was grown across three sites over two years, divided into four subgroups. GS analysis for HTI prediction was performed using marker data from three sequencing platforms and six marker densities with six statistical methods. Results: The findings indicate that a loosely attached husk can aid in the dissipation of water from kernels in temperate maize germplasms across most environments but not nessarily for tropical-origin maize. Considering the balance between GS prediction accuracy and breeding cost, the optimal prediction strategy is the rrBLUP model, the 50K sequencing platform, a 30% proportion of the test population, and a marker density of r2=0.1. Additionally, selecting a specific SS subgroup for sampling the testing set significantly enhances the predictive capacity for husk tightness. Discussion: The determination of the optimal GS prediction strategy for HTI provides an economically feasible reference for the practice of molecular breeding. It also serves as a reference method for GS breeding of other agronomic traits.

Comparative efficacy of aromatase inhibitors and gonadotropin-releasing hormone analogue in increasing final height of idiopathic short stature boys: a network meta-analysis.

Objective: To investigate the efficacy of monotherapy with AIs or GnRHa in improving the height of boys with idiopathic short stature (ISS). Method: We performed a systematic search in Pubmed, The Cochrane Library, Chinese National Knowledge Infrastructure databases, and Wanfang Database for eligible studies. The network meta-analysis was conducted using STATA software. Results: We identified a total of four studies that included 136 individuals. We used FAH/PAH as the main outcome of final height. The results revealed a statistically higher final height after treatment with AI or GnRHa in idiopathic short stature children(MD= 4.63, 95% CI[3.29,5.96]). In network meta-analysis, the direct and indirect comparison between AI and GnRHa was presented in the forest plot. Compared with control group, both AI and GnRHa were effective in increasing the final height, with the mean effect of 4.91(95%CI:1.10,8.17) and 5.55(95%CI:1.12,9.98) respectively. However, there was no statistical difference between the GnRHa and AI treatment, of which the mean effect was 0.65(95%CI: -4.30,5.60). Conclusion: Both AIs and GnRHa monotherapy were effective in augmenting the final height of boys with idiopathic short stature when compared to placebo groups. However, there was no statistical difference between the GnRHa and AI treatments.

Genome-Wide Association Study Identified Novel SNPs Associated with Chlorophyll Content in Maize.

Chlorophyll is an essential component that captures light energy to drive photosynthesis. Chlorophyll content can affect photosynthetic activity and thus yield. Therefore, mining candidate genes of chlorophyll content will help increase maize production. Here, we performed a genome-wide association study (GWAS) on chlorophyll content and its dynamic changes in 378 maize inbred lines with extensive natural variation. Our phenotypic assessment showed that chlorophyll content and its dynamic changes were natural variations with a moderate genetic level of 0.66/0.67. A total of 19 single-nucleotide polymorphisms (SNPs) were found associated with 76 candidate genes, of which one SNP, 2376873-7-G, co-localized in chlorophyll content and area under the chlorophyll content curve (AUCCC). Zm00001d026568 and Zm00001d026569 were highly associated with SNP 2376873-7-G and encoded pentatricopeptide repeat-containing protein and chloroplastic palmitoyl-acyl carrier protein thioesterase, respectively. As expected, higher expression levels of these two genes are associated with higher chlorophyll contents. These results provide a certain experimental basis for discovering the candidate genes of chlorophyll content and finally provide new insights for cultivating high-yield and excellent maize suitable for planting environment.