A common resequencing-based genetic marker data set for global maize diversity.

Maize (Zea mays ssp. mays) populations exhibit vast ranges of genetic and phenotypic diversity. As sequencing costs have declined, an increasing number of projects have sought to measure genetic differences between and within maize populations using whole-genome resequencing strategies, identifying millions of segregating single-nucleotide polymorphisms (SNPs) and insertions/deletions (InDels). Unlike older genotyping strategies like microarrays and genotyping by sequencing, resequencing should, in principle, frequently identify and score common genetic variants. However, in practice, different projects frequently employ different analytical pipelines, often employ different reference genome assemblies and consistently filter for minor allele frequency within the study population. This constrains the potential to reuse and remix data on genetic diversity generated from different projects to address new biological questions in new ways. Here, we employ resequencing data from 1276 previously published maize samples and 239 newly resequenced maize samples to generate a single unified marker set of approximately 366 million segregating variants and approximately 46 million high-confidence variants scored across crop wild relatives, landraces as well as tropical and temperate lines from different breeding eras. We demonstrate that the new variant set provides increased power to identify known causal flowering-time genes using previously published trait data sets, as well as the potential to track changes in the frequency of functionally distinct alleles across the global distribution of modern maize.

Unraveling Prevalence and Effects of Deleterious Mutations in Maize Elite Lines across Decades of Modern Breeding.

Future breeding is likely to involve the detection and removal of deleterious alleles, which are mutations that negatively affect crop fitness. However, little is known about the prevalence of such mutations and their effects on phenotypic traits in the context of modern crop breeding. To address this, we examined the number and frequency of deleterious mutations in 350 elite maize inbred lines developed over the past few decades in China and the United States. Our findings reveal an accumulation of weakly deleterious mutations and a decrease in strongly deleterious mutations, indicating the dominant effects of genetic drift and purifying selection for the two types of mutations, respectively. We also discovered that slightly deleterious mutations, when at lower frequencies, were more likely to be heterozygous in the developed hybrids. This is consistent with complementation as a potential explanation for heterosis. Subsequently, we found that deleterious mutations accounted for more of the variation in phenotypic traits than nondeleterious mutations with matched minor allele frequencies, especially for traits related to leaf angle and flowering time. Moreover, we detected fewer deleterious mutations in the promoter and gene body regions of differentially expressed genes across breeding eras than in nondifferentially expressed genes. Overall, our results provide a comprehensive assessment of the prevalence and impact of deleterious mutations in modern maize breeding and establish a useful baseline for future maize improvement efforts.

The Heterogeneity in the Landscape of Gene Dominance in Maize is Accompanied by Unique Chromatin Environments.

Subgenome dominance after whole-genome duplication (WGD) has been observed in many plant species. However, the degree to which the chromatin environment affects this bias has not been explored. Here, we compared the dominant subgenome (maize1) and the recessive subgenome (maize2) with respect to patterns of sequence substitutions, genes expression, transposable element accumulation, small interfering RNAs, DNA methylation, histone modifications, and accessible chromatin regions (ACRs). Our data show that the degree of bias between subgenomes for all the measured variables does not vary significantly when both of the WGD genes are located in pericentromeric regions. Our data further indicate that the location of maize1 genes in chromosomal arms is pivotal for maize1 to maintain its dominance, but location has a less effect on maize2 homoeologs. In addition to homoeologous genes, we compared ACRs, which often harbor cis-regulatory elements, between the two subgenomes and demonstrate that maize1 ACRs have a higher level of chromatin accessibility, a lower level of sequence substitution, and are enriched in chromosomal arms. Furthermore, we find that a loss of maize1 ACRs near their nearby genes is associated with a reduction in purifying selection and expression of maize1 genes relative to their maize2 homoeologs. Taken together, our data suggest that chromatin environment and cis-regulatory elements are important determinants shaping the divergence and evolution of duplicated genes.

Human breast milk-derived exosomes through inhibiting AT II cell apoptosis to prevent bronchopulmonary dysplasia in rat lung.

Human breast milk (HBM) effectively prevents and cures neonatal bronchopulmonary dysplasia (BPD). Exosomes are abundant in breast milk, but the function of HBM-derived exosomes (HBM-Exo) in BPD is still unclear. This study was to investigate the role and mechanism of HBM-Exo in BPD. Overall lung tissue photography and H&E staining showed that HBM-Exo improved the lung tissue structure collapse, alveolar structure disorder, alveolar septum width, alveolar number reduction and other injuries caused by high oxygen exposure. Immunohistochemical results showed that HBM-Exo improved the inhibition of cell proliferation and increased apoptosis caused by hyperoxia. qPCR and Western blot results also showed that HBM-Exo improved the expression of Type II alveolar epithelium (AT II) surface marker SPC. In vivo study, CCK8 and flow cytometry showed that HBM-Exo improved the proliferation inhibition and apoptosis of AT II cells induced by hyperoxia, qPCR and immunofluorescence also showed that HBM-Exo improved the down-regulation of SPC. Further RNA-Seq results in AT II cells showed that a total of 88 genes were significantly different between the hyperoxia and HBM-Exo with hyperoxia groups, including 24 up-regulated genes and 64 down-regulated genes. KEGG pathway analysis showed the enrichment of IL-17 signalling pathway was the most significant. Further rescue experiments showed that HBM-Exo improved AT II cell damage induced by hyperoxia through inhibiting downstream of IL-17 signalling pathway (FADD), which may be an important mechanism of HBM-Exo in the prevention and treatment of BPD. This study may provide new approach in the treatment of BPD.

Population genomics of Zea species identifies selection signatures during maize domestication and adaptation.

BACKGROUND: Maize (Zea mays L. ssp. mays) was domesticated from teosinte (Zea mays ssp. parviglumis) about 9000 years ago in southwestern Mexico and adapted to a range of environments worldwide. Researchers have depicted the maize domestication and adaptation processes over the past two decades, but efforts have been limited either in sample size or genetic diversity. To better understand these processes, we conducted a genome-wide survey of 982 maize inbred lines and 190 teosinte accessions using over 40,000 single-nucleotide polymorphism markers. RESULTS: Population structure, principal component analysis, and phylogenetic trees all confirmed the evolutionary relationship between maize and teosinte, and determined the evolutionary lineage of all species within teosinte. Shared haplotype analysis showed similar levels of ancestral alleles from Zea mays ssp. parviglumis and Zea mays ssp. mexicana in maize. Scans for selection signatures identified 394 domestication sweeps by comparing wild and cultivated maize and 360 adaptation sweeps by comparing tropical and temperate maize. Permutation tests revealed that the public association signals for flowering time were highly enriched in the domestication and adaptation sweeps. Genome-wide association study identified 125 loci significantly associated with flowering-time traits, ten of which identified candidate genes that have undergone selection during maize adaptation. CONCLUSIONS: In this study, we characterized the history of maize domestication and adaptation at the population genomic level and identified hundreds of domestication and adaptation sweeps. This study extends the molecular mechanism of maize domestication and adaptation, and provides resources for basic research and genetic improvement in maize.

An actin-like protein PoARP9 involves in the regulation of development and cellulase and amylase expression in Penicillium oxalicum.

AIMS: In eukaryotic cells, chromatin remodelling complexes are essential for the accessibility of transcription factors to the specific regulating regions of downstream genes. Here, we identified an actin-like protein PoARP9 in cellulase production strain Penicillium oxalicum 114-2, which was an essential member of SWI/SNF complex. To investigate the physiological function of PoARP9 in transcriptional regulation, the coding gene Poarp9 was deleted in P. oxalicum 114-2. METHODS AND RESULTS: The absence of PoARP9 affected the colony growth on medium with glucose, cellulose or starch as sole carbon source. Meanwhile, the expression levels of major cellulase genes were all upregulated in ΔPoarp9 under the cellulase-inducing condition. In addition, the expression levels of amylase transcription activator AmyR as well as two major amylase genes were also increased in ΔPoarp9. CONCLUSIONS: These results demonstrated that chromatin remodelling affects the development and expression of cellulase and amylase in P. oxalicum. And the SWI/SNF complex member PoARP9 plays essential roles in these processes. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provided new insights into the regulation of cellulase and development in P. oxalicum. And the regulatory function of SWI/SNF complex member ARP9 towards cellulase and amylase expression in P. oxalicum was verified for the first time.

Genetic basis of kernel nutritional traits during maize domestication and improvement.

The nutritional traits of maize kernels are important for human and animal nutrition, and these traits have undergone selection to meet the diverse nutritional needs of humans. However, our knowledge of the genetic basis of selecting for kernel nutritional traits is limited. Here, we identified both single and epistatic quantitative trait loci (QTLs) that contributed to the differences of oil and carotenoid traits between maize and teosinte. Over half of teosinte alleles of single QTLs increased the values of the detected oil and carotenoid traits. Based on the pleiotropism or linkage information of the identified single QTLs, we constructed a trait-locus network to help clarify the genetic basis of correlations among oil and carotenoid traits. Furthermore, the selection features and evolutionary trajectories of the genes or loci underlying variations in oil and carotenoid traits revealed that these nutritional traits produced diverse selection events during maize domestication and improvement. To illustrate more, a mutator distance-relative transposable element (TE) in intron 1 of DXS2, which encoded a rate-limiting enzyme in the methylerythritol phosphate pathway, was identified to increase carotenoid biosynthesis by enhancing DXS2 expression. This TE occurs in the grass teosinte, and has been found to have undergone selection during maize domestication and improvement, and is almost fixed in yellow maize. Our findings not only provide important insights into evolutionary changes in nutritional traits, but also highlight the feasibility of reintroducing back into commercial agricultural germplasm those nutritionally important genes hidden in wild relatives.

Patterns of genomic variation in Chinese maize inbred lines and implications for genetic improvement.

KEY MESSAGE: Genetic relationships among Chinese maize germplasms reveal historical trends in heterotic patterns from Chinese breeding programs and identify line Dan340 as a potential genome donor for elite inbred line Zheng58. The characterization of the genetic relationships, heterotic patterns and breeding history of lines in maize breeding programs allows breeders to efficiently use maize germplasm for line improvement over time. In this study, 269 temperate inbred lines, most of which have been widely used in Chinese maize breeding programs since the 1970s, were genotyped using the Illumina MaizeSNP50 BeadChip, which contains 56,110 single-nucleotide polymorphisms. The STRUCTURE analysis, cluster analysis and principal coordinate analysis results consistently revealed seven groups, of which five were consistent with known heterotic groups within the Chinese maize germplasm-Domestic Reid, Lancaster, Zi330, Tang SPT and Tem-tropic I (also known as "P"). These genetic relationships also allowed us to determine the historical trends in heterotic patterns during the three decades from 1970 to 2000, represented by Mo17 from Lancaster, HuangZaoSi (HZS) from Tang SPT, Ye478 from Domestic Reid and P178 from Tem-tropic I heterotic groups. Mo17-related commercial hybrids were widely used in the 1970s and 1980s, followed by the release of HZS- and Ye478-related commercial hybrids in the 1980s and 1990s, and the introduction of Tem-tropic I group in the 1990s and 2000s. Additionally, we identified inbred line Dan340 as a potential genome donor for Zheng58, which is the female parent of the most widely grown commercial hybrid ZhengDan958 in China. We also reconstructed the recombination events of elite line HZS and its 14 derived lines. These findings provide useful information to direct future maize breeding efforts.

Natural variations in stearoyl-acp desaturase genes affect the conversion of stearic to oleic acid in maize kernel.

KEY MESSAGE: We identified 11 SAD genes, and mined their natural variations associated with the conservation of stearic to oleic acid, especially ZmSAD1 supported by both the QTL and an expression QTL. Maize oil is generally regarded as a healthy vegetable oil owing to its low abundance of saturated fatty acids. Stearoyl-ACP desaturase (SAD) is a key rate-limiting enzyme for the conservation of stearic (C18:0) to oleic (C18:1) acid. Here, 11 maize SAD genes were identified to have more divergent functions than Arabidopsis SAD genes. The genomic regional associations in a maize panel including 508 inbred lines identified 6 SAD genes significantly associated (P < 0.01) with the C18:0/C18:1 ratio or the level of C18:0 or C18:1, one gene of which co-localized with a quantitative trait locus (QTL) and 5 of which co-localized with an expression QTL. ZmSAD1, supported by both the QTL and an expression QTL, had the largest effect on C18:0/C18:1. One nonsynonymous single-nucleotide polymorphism in exon 3 and one 5-bp insertion/deletion in the 3' untranslated region were further shown to contribute to the natural variation in C18:0/C18:1 according to ZmSAD1-based association mapping. Finally, selection tests of ZmSAD1 in teosinte, regular maize, and high-oil maize indicated that ZmSAD1 was not a selection target during the process of maize domestication and high-oil maize development. These results will guide the manipulation of the ratio between saturated and unsaturated fatty acids in maize.

Genome-wide dissection of the maize ear genetic architecture using multiple populations.

Improvement of grain yield is an essential long-term goal of maize (Zea mays) breeding to meet continual and increasing food demands worldwide, but the genetic basis remains unclear. We used 10 different recombination inbred line (RIL) populations genotyped with high-density markers and phenotyped in multiple environments to dissect the genetic architecture of maize ear traits. Three methods were used to map the quantitative trait loci (QTLs) affecting ear traits. We found 17-34 minor- or moderate-effect loci that influence ear traits, with little epistasis and environmental interactions, totally accounting for 55.4-82% of the phenotypic variation. Four novel QTLs were validated and fine mapped using candidate gene association analysis, expression QTL analysis and heterogeneous inbred family validation. The combination of multiple different populations is a flexible and manageable way to collaboratively integrate widely available genetic resources, thereby boosting the statistical power of QTL discovery for important traits in agricultural crops, ultimately facilitating breeding programs.

Genomic investigation of 18,421 lines reveals the genetic architecture of rice.

Understanding how numerous quantitative trait loci (QTL) shape phenotypic variation is an important question in genetics. To address this, we established a permanent population of 18,421 (18K) rice lines with reduced population structure. We generated reference-level genome assemblies of the founders and genotyped all 18K-rice lines through whole-genome sequencing. Through high-resolution mapping, 96 high-quality candidate genes contributing to variation in 16 traits were identified, including OsMADS22 and OsFTL1 verified as causal genes for panicle number and heading date, respectively. We identified epistatic QTL pairs and constructed a genetic interaction network with 19 genes serving as hubs. Overall, 170 masking epistasis pairs were characterized, serving as an important factor contributing to genetic background effects across diverse varieties. The work provides a basis to guide grain yield and quality improvements in rice.

A Real-Time Registration Algorithm of UAV Aerial Images Based on Feature Matching.

This study aimed to achieve the accurate and real-time geographic positioning of UAV aerial image targets. We verified a method of registering UAV camera images on a map (with the geographic location) through feature matching. The UAV is usually in rapid motion and involves changes in the camera head, and the map is high-resolution and has sparse features. These reasons make it difficult for the current feature-matching algorithm to accurately register the two (camera image and map) in real time, meaning that there will be a large number of mismatches. To solve this problem, we used the SuperGlue algorithm, which has a better performance, to match the features. The layer and block strategy, combined with the prior data of the UAV, was introduced to improve the accuracy and speed of feature matching, and the matching information obtained between frames was introduced to solve the problem of uneven registration. Here, we propose the concept of updating map features with UAV image features to enhance the robustness and applicability of UAV aerial image and map registration. After numerous experiments, it was proved that the proposed method is feasible and can adapt to the changes in the camera head, environment, etc. The UAV aerial image is stably and accurately registered on the map, and the frame rate reaches 12 frames per second, which provides a basis for the geo-positioning of UAV aerial image targets.

Estimating the genetic parameters of yield-related traits under different nitrogen conditions in maize.

Understanding the genetic basis responding to nitrogen (N) fertilization in crop production is a long-standing research topic in plant breeding and genetics. Albeit years of continuous efforts, the genetic architecture parameters, such as heritability, polygenicity, and mode of selection, underlying the N responses in maize remain largely unclear. In this study, about n = 230 maize inbred lines were phenotyped under high N (HN) and low N (LN) conditions for 2 consecutive years to obtain 6 yield-related traits. Heritability analyses suggested that traits highly responsive to N treatments were less heritable. Using publicly available SNP genotypes, the genome-wide association study (GWAS) was conducted to identify n = 237 and n = 130 trait-associated loci under HN and LN conditions, n = 164 for N-responsive (NR) traits, and n = 31 for genotype by N interaction (G × N). Furthermore, genome-wide complex trait Bayesian (GCTB) analysis, a method complementary to GWAS, was performed to estimate genetic parameters, including genetic polygenicity and the mode of selection (S). GCTB results suggested that the NR value of a yield component trait was highly polygenic and that 4 NR traits exhibited negative correlations between SNP effects and their minor allele frequencies (or the S value <0)-a pattern consistent with negative selection to purge deleterious alleles. This study reveals the complex genetic architecture underlying N responses for yield-related traits and provides candidate genetic loci for N resilient maize improvement.

Phosducin-like protein PoPlp1 impacts cellulase and amylase expression and development in Penicillium oxalicum via the G protein-cAMP signaling pathway.

In this study, a phosducin-like protein, PoPlp1, was identified and functionally studied in the cellulase-producing strain Penicillium oxalicum 114-2. PoPlp1 was proven to participate in several biological processes, including mycelium development, conidiation, and expression of cellulases and amylases. With deletion of Poplp1, morphology and development varied significantly in ΔPoplp1. Colony growth, glucose utilization, and the hydrolysis capability of starch and cellulose were limited, whereas conidiation was enhanced. Based on detection of the levels of expression of transcription factors involved in asexual development, we conjectured that PoPlp1 is involved in conidiation via the major factor BrlA. We explored the effect of PoPlp1 on cellulase and amylase expression and observed that cellulase and amylase activity and major gene transcription levels were all dramatically reduced in ΔPoplp1. Deletion of PoPlp1 caused a decrease in intracellular cAMP levels, and the cellulase gene expression level of ΔPoplp1 was restored to a certain extent through external addition of cAMP. These findings demonstrate that PoPlp1 may affect cellulase and amylase expression by regulating cAMP concentration. To comprehensively explore the mechanism of PoPlp1 in regulating multiple biological processes, we performed a comparative transcriptomic analysis between strains P. oxalicum 114-2 and ΔPoplp1. The major cellulase and amylase genes were all downregulated, congrent with the results of real-time quantitative polymerase chain reaction analysis. The genes involved in the G protein-cAMP signaling pathway, including several G-protein-coupled receptors, one regulator of G protein signaling, and two cAMP phosphodiesterases, were disrupted by deletion of PoPlp1. These results confirm the positive function of PoPlp1 in the G protein-cAMP signaling pathway. This functional analysis of PoPlp1 will be very beneficial for further study of the regulatory mechanisms of cellulase expression and other biological processes in P. oxalicum 114-2 via the G protein-cAMP signaling pathway.

Functional Study of cAMP-Dependent Protein Kinase A in Penicillium oxalicum.

Signaling pathways play a crucial role in regulating cellulase production. The pathway mediated by signaling proteins plays a crucial role in understanding how cellulase expression is regulated. In this study, using affinity purification of ClrB, we have identified sixteen proteins that potentially interact with ClrB. One of the proteins, the catalytic subunit of cAMP-dependent protein kinase A (PoPKA-C), is an important component of the cAMP/PKA signaling pathway. Knocking out PoPKA-C resulted in significant decreases in the growth, glucose utilization, and cellulose hydrolysis ability of the mutant strain. Furthermore, the cellulase activity and gene transcription levels were significantly reduced in the ΔPoPKA-C mutant, while the expression activity of CreA, a transcriptional regulator of carbon metabolism repression, was notably increased. Additionally, deletion of PoPKA-C also led to earlier timing of conidia production. The expression levels of key transcription factor genes stuA and brlA, which are involved in the production of the conidia, showed significant enhancement in the ΔPoPKA-C mutant. These findings highlight the involvement of PoPKA-C in mycelial development, conidiation, and the regulation of cellulase expression. The functional analysis of PoPKA-C provides insights into the mechanism of the cAMP/PKA signaling pathway in cellulase expression in filamentous fungi and has significant implications for the development of high-yielding cellulase strains.

Genome-wide mediation analysis: an empirical study to connect phenotype with genotype via intermediate transcriptomic data in maize.

Mapping genotype to phenotype is an essential topic in genetics and genomics research. As the Omics data become increasingly available, 2-variable methods have been widely applied to associate genotype with the phenotype (genome-wide association study), gene expression with the phenotype (transcriptome-wide association study), and genotype with gene expression. However, signals detected by these 2-variable association methods suffer from low mapping resolution or inexplicit causality between genotype and phenotype, making it challenging to interpret and validate the molecular mechanisms of the underlying genomic variations and the candidate genes. Under the context of genetics research, we hypothesized a causal chain from genotype to phenotype partially mediated by intermediate molecular processes, i.e. gene expression. To test this hypothesis, we applied the high-dimensional mediation analysis, a class of causal inference method with an assumed causal chain from the exposure to the mediator to the outcome, and implemented it with a maize association panel (N = 280 lines). Using 40 publicly available agronomy traits, 66 newly generated metabolite traits, and published RNA-seq data from 7 different tissues, our empirical study detected 736 unique mediating genes. Noticeably, 83/736 (11%) genes were identified in mediating more than 1 trait, suggesting the prevalence of pleiotropic mediating effects. We demonstrated that several identified mediating genes are consistent with their known functions. In addition, our results provided explicit hypotheses for functional validation and suggested that the mediation analysis is a powerful tool to integrate Omics data to connect genotype to phenotype.

Recombinant Bifidobacterium longum Carrying Endostatin Protein Alleviates Dextran Sodium Sulfate-Induced Colitis and Colon Cancer in Rats.

Bifidobacterium has been widely administrated orally as probiotics to prevent pathogen colonization and modulate the gut microbiome balance. Endostatin is an endogenous inhibitor of angiogenesis and has been shown to inhibit tumor growth, invasion, and metastasis. At present, the combination of endostatin and chemotherapeutic drugs has been regarded as a promising antitumor treatment strategy. In this study, we selected a safe strain of Bifidobacterium longum as a delivery system to transport endostatin to the gastrointestinal tract and explored their combined effect on inflammatory bowel disease (IBD) and colitis-associated cancer. The results indicated that B. longum-Endo relieved dextran sulfate sodium-induced body weight loss, diarrhea, colon shortening, and epithelium damage. Long-term oral administration of B. longum-Endo significantly decreased tumor formation rate, tumor number, and tumor size. Moreover, the effect of B. longum-Endo on gut microbiota dysbiosis was also confirmed by 16S rRNA sequencing analysis. The levels of potentially beneficial bacteria, such as Lactobacillus, Bifidobacterium, Allobaculum, and Parabateroides, were increased in the B. longum-Endo group compared to the model and B. longum groups. Meanwhile, levels of potentially pathogenic bacteria including Desulfovibrio, Helicobacter, and Enterorhabdus were decreased. Taken together, these results suggested that oral administration of recombinant B. longum-Endo strain may be a promising therapeutic strategy for IBD and colitis-associated cancer.

Association analyses of host genetics, root-colonizing microbes, and plant phenotypes under different nitrogen conditions in maize.

The root-associated microbiome (rhizobiome) affects plant health, stress tolerance, and nutrient use efficiency. However, it remains unclear to what extent the composition of the rhizobiome is governed by intraspecific variation in host plant genetics in the field and the degree to which host plant selection can reshape the composition of the rhizobiome. Here, we quantify the rhizosphere microbial communities associated with a replicated diversity panel of 230 maize (Zea mays L.) genotypes grown in agronomically relevant conditions under high N (+N) and low N (-N) treatments. We analyze the maize rhizobiome in terms of 150 abundant and consistently reproducible microbial groups and we show that the abundance of many root-associated microbes is explainable by natural genetic variation in the host plant, with a greater proportion of microbial variance attributable to plant genetic variation in -N conditions. Population genetic approaches identify signatures of purifying selection in the maize genome associated with the abundance of several groups of microbes in the maize rhizobiome. Genome-wide association study was conducted using the abundance of microbial groups as rhizobiome traits, and n=622 plant loci were identified that are linked to the abundance of n=104 microbial groups in the maize rhizosphere. In 62/104 cases, which is more than expected by chance, the abundance of these same microbial groups was correlated with variation in plant vigor indicators derived from high throughput phenotyping of the same field experiment. We provide comprehensive datasets about the three-way interaction of host genetics, microbe abundance, and plant performance under two N treatments to facilitate targeted experiments toward harnessing the full potential of root-associated microbial symbionts in maize production.

Convergent selection of a WD40 protein that enhances grain yield in maize and rice.

A better understanding of the extent of convergent selection among crops could greatly improve breeding programs. We found that the quantitative trait locus KRN2 in maize and its rice ortholog, OsKRN2, experienced convergent selection. These orthologs encode WD40 proteins and interact with a gene of unknown function, DUF1644, to negatively regulate grain number in both crops. Knockout of KRN2 in maize or OsKRN2 in rice increased grain yield by ~10% and ~8%, respectively, with no apparent trade-offs in other agronomic traits. Furthermore, genome-wide scans identified 490 pairs of orthologous genes that underwent convergent selection during maize and rice evolution, and these were enriched for two shared molecular pathways. KRN2, together with other convergently selected genes, provides an excellent target for future crop improvement.

Correlation Between Pulmonary Sclerosing Pneumocytoma Features and MSCT Imaging Manifestations in 34 Patients: Implications for Precision Medicine.

Objective: To identify and analyze the multi-slice computed tomography (MSCT) imaging manifestations and clinicopathological features of PSP to improve the preoperative and intraoperative diagnosis of the disease. Method: This was a retrospective study conducted on the imaging and clinicopathological data of the PSP patients treated in two major hospitals in China from October 2001 to December 2019. The locations of lung lesions, clinical symptoms, surgical complications, MSCT imaging features, and the corresponding relationship with clinicopathological features were assessed. Then, a new diagnostic approach was defined and used to train imaging and pathological doctors (experimental group). Then, the diagnostic accuracy of the experimental group was evaluated in preoperative and intraoperative diagnosis of PSP. Results: Thirty-four PSP cases were analyzed (mean: 51.42; range: 39-69 years old). The peripheral type was more common, while 92% of the lesions located in the middle lobe of the right lung and the lower lobe of bilateral lungs. The shortest lesion edge-pleura distance ranged 0 to 30 mm and 46% of the lesions (16/34) were attached to the pleura, 62% (21/34) located at 0-5 mm, 92% (31/34) within 20 mm from the pleura. Diameters of the lesions ranged 8.58 to 68.41 mm, while most of them were 20-40 mm. All lesions showed enhancement, and 97% (33/34) were unevenly enhanced. PSP volume was negatively correlated with the total degree of enhancement (r = -0.587, p < 0.01), and the volume difference between the obvious enhancement zone and the slight enhancement zone (r = -0.795, p < 0.01). Welt vessel sign was observed in 61.7% (21/34) of cases, and none of welt vessels entered into the lesions. Vascular-like enhancement area inside the lesion showed no significant correlation with the welt vessels outside the lesion, and no case showed entrance of bronchus into the lesion. The trained experimental group showed significantly greater diagnostic accuracy than the control group. In particular, the accuracy rate of intraoperative frozen section diagnosis was 60% higher in the experimental group than the control group. Conclusion: PSP has characteristic imaging manifestations, which can be utilized to improve the preoperative and intraoperative diagnostic coincidence rate of PSP.