Maize smart-canopy architecture enhances yield at high densities.

Increasing planting density is a key strategy for enhancing maize yields1-3. An ideotype for dense planting requires a 'smart canopy' with leaf angles at different canopy layers differentially optimized to maximize light interception and photosynthesis4-6, among other features. Here we identified leaf angle architecture of smart canopy 1 (lac1), a natural mutant with upright upper leaves, less erect middle leaves and relatively flat lower leaves. lac1 has improved photosynthetic capacity and attenuated responses to shade under dense planting. lac1 encodes a brassinosteroid C-22 hydroxylase that predominantly regulates upper leaf angle. Phytochrome A photoreceptors accumulate in shade and interact with the transcription factor RAVL1 to promote its degradation via the 26S proteasome, thereby inhibiting activation of lac1 by RAVL1 and decreasing brassinosteroid levels. This ultimately decreases upper leaf angle in dense fields. Large-scale field trials demonstrate that lac1 boosts maize yields under high planting densities. To quickly introduce lac1 into breeding germplasm, we transformed a haploid inducer and recovered homozygous lac1 edits from 20 diverse inbred lines. The tested doubled haploids uniformly acquired smart-canopy-like plant architecture. We provide an important target and an accelerated strategy for developing high-density-tolerant cultivars, with lac1 serving as a genetic chassis for further engineering of a smart canopy in maize.

miR-30 inhibits the progression of osteosarcoma by targeting MTA1.

OBJECTIVES: MicroRNAs (miRNAs) have been considered as a new class of novel diagnostic and predictive biomarker in many diseases. However, there are few studies on miRNA in osteosarcoma (OS). This study aimed to investigate the roles of miR-30 on OS occurrence and development. METHODS: PCR was used to detect mRNA levels of miR-30 and MTA1 in cancer tissues, adjacent non-cancerous tissues from OS patients. Western blot was used to detect MTA1 protein expression in all tissues and cell lines (hFOb1.19,Saos-2, MG63, and U2OS). The correlation between miR-30 and MTA1 was predicted through bioinformatics software, and identified by a luciferase reporting experiment. In vitro, functional test detected the specific effects of miR-30 and MTA1 on the development of OS. RESULTS: miR-30 expression was significantly reduced, while the expression of MTA1 was increased in OS tissues and cells. Luciferase reporting experiment showed that miR-30 sponged MTA1 which was negatively correlated with miR-30 expression. Furthermore, rescue tests revealed that MTA1 restrained the functions of miR-30 on cell proliferation and migration of OS. CONCLUSION: Our finding showed that miR-30 modulated the proliferation and migration by targeting MTA1 in OS.

Neoxanthin affects the stability of the C2 S2 M2 -type photosystem II supercomplexes and the kinetics of state transition in Arabidopsis.

Neoxanthin (Neo), which is only bound to the peripheral antenna proteins of photosystem (PS) II, is a conserved carotenoid in all green plants. It has been demonstrated that Neo plays an important role in photoprotection and its deficiency fails to impact LHCII stability in vitro and indoor plant growth in vivo. Whether Neo is involved in maintaining the PSII complex structure or adaptive mechanisms for the everchanging environment has not yet been elucidated. In this study, the role of Neo in maintaining the structure and function of the PSII-LHCII supercomplexes was studied using Neo deficient Arabidopsis mutants. Our results show that Neo deficiency had little effect on the electron transport capacity and the plant fitness, but the PSII-LHCII supercomplexes were significantly impacted by the lack of Neo. In the absence of Neo, the M-type LHCII trimer cannot effectively associate with the C2 S2 -type PSII-LHCII supercomplexes even in moderate light conditions. Interestingly, Neo deficiency also leads to decreased PSII protein phosphorylation but rapid transition from state 1 to state 2. We suggest that Neo might enforce the interactions between LHCII and the minor antennas and that the absence of Neo makes M-type LHCII disassociate from the PSII complex, leading to the disassembly of the PSII-LHCII C2 S2 M2 supercomplexes, which results in alterations in the phosphorylation patterns of the thylakoid photosynthetic proteins and the kinetics of state transition.

ZmCCT9 enhances maize adaptation to higher latitudes.

From its tropical origin in southwestern Mexico, maize spread over a wide latitudinal cline in the Americas. This feat defies the rule that crops are inhibited from spreading easily across latitudes. How the widespread latitudinal adaptation of maize was accomplished is largely unknown. Through positional cloning and association mapping, we resolved a flowering-time quantitative trait locus to a Harbinger-like transposable element positioned 57 kb upstream of a CCT transcription factor (ZmCCT9). The Harbinger-like element acts in cis to repress ZmCCT9 expression to promote flowering under long days. Knockout of ZmCCT9 by CRISPR/Cas9 causes early flowering under long days. ZmCCT9 is diurnally regulated and negatively regulates the expression of the florigen ZCN8, thereby resulting in late flowering under long days. Population genetics analyses revealed that the Harbinger-like transposon insertion at ZmCCT9 and the CACTA-like transposon insertion at another CCT paralog, ZmCCT10, arose sequentially following domestication and were targeted by selection for maize adaptation to higher latitudes. Our findings help explain how the dynamic maize genome with abundant transposon activity enabled maize to adapt over 90° of latitude during the pre-Columbian era.

ZmMADS69 functions as a flowering activator through the ZmRap2.7-ZCN8 regulatory module and contributes to maize flowering time adaptation.

Flowering time is a major determinant of the local adaptation of plants. Although numerous loci affecting flowering time have been mapped in maize, their underlying molecular mechanisms and roles in adaptation remain largely unknown. Here, we report the identification and characterization of MADS-box transcription factor ZmMADS69 that functions as a flowering activator through the ZmRap2.7-ZCN8 regulatory module and contributes to adaptation. We show that ZmMADS69 underlies a quantitative trait locus controlling the difference in flowering time between maize and its wild ancestor, teosinte. Maize ZmMADS69 allele is expressed at a higher level at floral transition and confers earlier flowering than the teosinte allele under long days and short days. Overexpression of ZmMADS69 causes early flowering, while a transposon insertion mutant of ZmMADS69 exhibits delayed flowering. ZmMADS69 shows pleiotropic effects for multiple traits of agronomic importance. ZmMADS69 functions upstream of the flowering repressor ZmRap2.7 to downregulate its expression, thereby relieving the repression of the florigen gene ZCN8 and causing early flowering. Population genetic analyses showed that ZmMADS69 was a target of selection and may have played an important role as maize spread from the tropics to temperate zones. Our findings provide important insights into the regulation and adaptation of flowering time.

The genetic architecture of leaf number and its genetic relationship to flowering time in maize.

The number of leaves and their distributions on plants are critical factors determining plant architecture in maize (Zea mays), and leaf number is frequently used as a measure of flowering time, a trait that is key to local environmental adaptation. Here, using a large set of 866 maize-teosinte BC2 S3 recombinant inbred lines genotyped by using 19,838 single nucleotide polymorphism markers, we conducted a comprehensive genetic dissection to assess the genetic architecture of leaf number and its genetic relationship to flowering time. We demonstrated that the two components of total leaf number, the number of leaves above (LA) and below (LB) the primary ear, were under relatively independent genetic control and might be subject to differential directional selection during maize domestication and improvement. Furthermore, we revealed that flowering time and leaf number are commonly regulated at a moderate level. The pleiotropy of the genes ZCN8, dlf1 and ZmCCT on leaf number and flowering time were validated by near-isogenic line analysis. Through fine mapping, qLA1-1, a major-effect locus that specifically affects LA, was delimited to a region with severe recombination suppression derived from teosinte. This study provides important insights into the genetic basis of traits affecting plant architecture and adaptation. The genetic independence of LA from LB enables the optimization of leaf number for ideal plant architecture breeding in maize.

The effective mode of growth and differentiation factor-5 in promoting the chondrogenic differentiation of adipose-derived stromal cells.

Our study aimed to find out the most effective mode for chondrogenic differentiation based on time, dose and culture method. ADSCs were cultured and identified by CD44, CD49d, and CD106 immumohistochemical staining method, and their differentiation potential to chondrocyte were detected by Alizarin red staining. ADSCs induced by different concentrations of GDF-5 for chondrogenic differentiation were detected by blue and toluidine blue staining and collagen type II and X immumohistochemical staining. The expression of collagen I, II, X and aggrecan gene in GDF-induced ADSCs cultured in 2- and 3-dimension was identified by real-time PCR. Cell microstructure and proliferation in three-dimensional scaffolds at day 7, 14, 21 and 28 were analyzed by scanning electron microscopy and MTS assay. The ADSCs were successfully identified by CD44 and CD49d, and their differentiation potential was detected by Alizarin red staining. Real-time PCR showed that collagen and aggrecan were expressed at high levels in 100 or 200 ng/mL GDF-5 treated cells. The collagen types (I, II) and aggrecan genes were higher expressed in GDF-5 induced scaffold group than that in monolayer group. MTS showed that the cell counts were not significantly different among different treated time. Both collagen type II and aggrecan gene were highly expressed at day 14, while collagen types I and X gene expressions peaked at day 21 and 28. The 100 ng/mL GDF-5 is effective and cost-effective for chondrogenic differentiation when cultured at day 14 in vitro under three-dimensional culture conditions.

Identification of genes associated with the differentiation potential of adipose-derived stem cells to osteocytes or myocytes.

Adipose-derived stem cells (ADSCs) have been considered as the optimal cells for regenerative medicine because ADSCs have the potential of multi-directional differentiation. To study the mechanisms of ADSCs differentiation, we analyzed microarray of GSE37329. GSE37329 was downloaded from Gene Expression Omnibus including 3 ADSCs, 2 ADSCs-derived osteocytes, and 2 ADSCs-derived myocytes samples. The differentially expressed genes (DEGs) were screened using limma package. Their underlying functions were predicted by gene ontology and pathway enrichment analyses. Besides, the interaction relationships of the proteins encoded by DEGs were obtained from STRING database, and protein-protein interaction (PPI) network was constructed using Cytoscape. Furthermore, modules analysis of PPI network was performed using MCODE in Cytoscape. We screened 662 and 484 DEG separately for the ADSCs-derived osteocytes and myocytes compared with ADSCs. There were 205 common up-regulated and 128 common down-regulated DEGs between the two groups. Function enrichment indicated that these common DEGs, especially, VEGFA, FGF2, and EGR1 may be related to cell differentiation. PPI network for common DEGs also suggested that VEGFA (degree = 29), FGF2 (degree = 17), and EGR1 (degree = 12) might be more important because they had higher connectivity degrees, and they might be involved in cell differentiation by interacting with other genes in module A (e.g., EGR1-NGF and EGR1-LEP), and B (e.g., VEGFA-PDGFD). Additionally, the IGF1 and BTG1 may be, respectively, specific for osteocytes and myocytes differentiation. VEGFA, PDGFD, FGF2, EGR1, NGF, LEP, IGF1, and BTG1 might serve as target genes in regulating ADSCs differentiation.

lncRNA TUSC7 inhibits osteosarcoma progression through the miR­181a/RASSF6 axis.

Osteosarcoma (OS) is one of the most aggressive malignancies, accompanied by an elevated incidence and a decreased rate of healing. Recently, several long non­coding RNAs (lncRNAs) have been reported to be involved in OS progression. Although tumor suppressor candidate 7 (TUSC7) was reported as a novel lncRNA, little is known about its biological functions in OS. The present study was designed to explore whether TUSC7 was involved in the pathological development of OS using various methods, including hematoxylin and eosin staining, Cell Counting Kit­8 assay, colony formation assay and Transwell assay. The present study revealed that TUSC7 expression was downregulated in OS tissues and cell lines compared with in normal tissues and cell lines. Functionally, the current results revealed that overexpression of TUSC7 inhibited OS cell proliferation, migration and invasion, while promoting apoptosis in vitro and in vivo. Next, the subcellular distribution of TUSC7 was examined by nuclear/cytoplasmic RNA fractionation and reverse transcription­quantitative PCR. Mechanistic studies revealed that TUSC7 exerted its role by sponging microRNA (miR)­181a in OS cell lines. Ras association domain family member 6 (RASSF6) was confirmed as a target gene of miR­181a, and the expression levels of RASSF6 were negatively regulated by miR­181a. Additionally, the results of rescue experiments suggested that overexpression of miR­181a neutralized the inhibitory effects of TUSC7 overexpression on OS cells. Overall, the present study demonstrated that the tumor suppressor role of TUSC7 in OS progression was mediated through the miR­181a/RASSF6 axis, which may represent a new therapeutic target for OS.

Sacral and thoracic chordoma with pulmonary metastases: A case report and review of the literature.

Chordoma is a sporadic type of cancer that affects the spine and is particularly challenging to treat due to the paucity of reported cases and scientific literature. In particular, primary chordomas affecting both the sacral and thoracic vertebrae are extremely rare. We herein report a rare case of chordoma in the sacral and thoracic vertebrae with pulmonary metastasis, along with a literature review. The objective of the present study was to explore treatment options and long-term outcomes in patients with metastatic chordoma. Posterior decompression was performed for the thoracic tumor, followed by extended resection of the sacral tumor. The symptoms of the patient were relieved after surgery, and the postoperative Nurick score decreased from grade 3 to grade 2, while the postoperative McCormick score was I. Therefore, complete chordoma excision and internal spinal fixation may effectively reduce tumor recurrence and metastasis.

Carcinoma-associated fibroblasts promote the proliferation and metastasis of osteosarcoma by transferring exosomal LncRNA SNHG17.

Cancer-associated fibroblasts (CAFs) serve as a predominant regulator in the tumor microenvironment. However, the crosstalk between CAFs and OS cells remains mostly unclear. Recent studies explored that long non-coding RNA (LncRNAs) involved in regulating osteosarcoma (OS) formation and development, but their functions in CAFs are unknown. Here, we first investigated the SNHG17 was upregulated in OS tissues and correlated with the poor prognosis through the integrating clinical data. We then evaluated the function of SNHG17 in vitro using the stable SNHG17-depleted OS cells. HOS cells with SNHG17 knocked down were performed to generate the OS xenograft model. Through immunohistochemistry assay and TUNEL apoptosis assay, the role of SNHG17 on OS development was assessed in vivo. We then examined the SNHG17 expression in exosomes derived from CAFs, normal fibroblasts (NFs), and tumor tissues from the OS clinical samples. The interaction among SNHG17, miR-2861, and MMP2 was predicted by bioinformatics analysis and identified by RIP and luciferase assays. The cell proliferation, migration, and apoptosis of SJSA-1 and HOS cells co-cultured with CAFs-derived exosomes were assessed by CCK-8 and colony formation assays. We found that SNHG17 was upregulated in the tumor tissues and presented a pro-tumorigenic effect on OS both in vitro and in vivo. It also was an essential exosomal cargo of CAFs and could affect OS cell proliferation and migration in vitro. CAFs-released exosomal SNHG17 acted as an essential molecular sponge for miR-2861 in OS cells. Moreover, MMP2 was a direct target of miR-2861 and was regulated by SNHG17. Overall, our findings identified that SNHG17 was an essential exosomal cargo of OS-related CAFs that contributes to proliferation and metastasis of OS, supporting the therapeutic potency of targeting the crosstalk between cancer cells and CAFs.

Photosynthetic inner antenna CP47 plays important roles in ephemeral plants in adapting to high light stress.

Throughout 3.5 billion years of evolution, photosynthesis of land plants has developed a complicated antenna system to cope with the ever-changing environments. The antenna system of photosystem (PS) II includes the outer antennae and inner antennae. The inner antennae CP43 and CP47, located in the closest peripheral of PSII reaction center (RC), play important roles in facilitating excitation energy transport from the outer antennae to the PSII RC. Although PSII RC is the last station of energy transport, it is the inner antenna CP47, not the RC, which possesses the lowest energy level in PSII. Berteroa incana (B. incana), which is a vascular plant grown in the Gobi region, can sustain very high photosynthesis capacity under very high light conditions. It has been discovered that the thylakoid membrane of B. incana possesses a unique low fluorescence emission spectrum because the fluorescence emission of CP47 (695 nm) is the main fluorescence emission peak of PSII. In this paper, the thylakoid membrane, isolated from B. incana grown under a light condition of 100 µM photons m-2 s-1 and subjected to high light treatment (1600 µM photons m-2 s-1 for 1.5 h or 3 h) was employed for the research. It has been found that the high fluorescence emission of CP47 decreased remarkably upon exposure to the high light treatment. Further observation revealed that the drastic changes in the CP47 fluorescence emission were accompanied by a slight reduction in the amount of CP47 and an enhancement of the CP29-LHCII-CP24 assembly. It is proposed that CP47 enables the functional switch between the excitation energy transfer towards PSII RC, and the overexcitation quenching in the PSII core. Together with CP43, CP47 plays important roles in regulating excitation energy distribution in PSII core complexes.

Teosinte ligule allele narrows plant architecture and enhances high-density maize yields.

Increased planting densities have boosted maize yields. Upright plant architecture facilitates dense planting. Here, we cloned UPA1 (Upright Plant Architecture1) and UPA2, two quantitative trait loci conferring upright plant architecture. UPA2 is controlled by a two-base sequence polymorphism regulating the expression of a B3-domain transcription factor (ZmRAVL1) located 9.5 kilobases downstream. UPA2 exhibits differential binding by DRL1 (DROOPING LEAF1), and DRL1 physically interacts with LG1 (LIGULELESS1) and represses LG1 activation of ZmRAVL1 ZmRAVL1 regulates brd1 (brassinosteroid C-6 oxidase1), which underlies UPA1, altering endogenous brassinosteroid content and leaf angle. The UPA2 allele that reduces leaf angle originated from teosinte, the wild ancestor of maize, and has been lost during maize domestication. Introgressing the wild UPA2 allele into modern hybrids and editing ZmRAVL1 enhance high-density maize yields.

Spring Ephemerals Adapt to Extremely High Light Conditions via an Unusual Stabilization of Photosystem II.

Ephemerals, widely distributed in the Gobi desert, have developed significant characteristics to sustain high photosynthetic efficiency under high light (HL) conditions. Since the light reaction is the basis for photosynthetic conversion of solar energy to chemical energy, the photosynthetic performances in thylakoid membrane of the spring ephemerals in response to HL were studied. Three plant species, namely two C3 spring ephemeral species of Cruciferae: Arabidopsis pumila (A. pumila) and Sisymbrium altissimum (S. altissimum), and the model plant Arabidopsis thaliana (A. thaliana) were chosen for the study. The ephemeral A. pumila, which is genetically close to A. thaliana and ecologically in the same habitat as S. altissimum, was used to avoid complications arising from the superficial differences resulted from comparing plants from two extremely contrasting ecological groups. The findings manifested that the ephemerals showed significantly enhanced activities of photosystem (PS) II under HL conditions, while the activities of PSII in A. thaliana were markedly decreased under the same conditions. Detailed analyses of the electron transport processes revealed that the increased plastoquinone pool oxidization, together with the enhanced PSI activities, ensured a lowered excitation pressure to PSII of both ephemerals, and thus facilitated the photosynthetic control to avoid photodamage to PSII. The analysis of the reaction centers of the PSs, both in terms of D1 protein turnover kinetics and the long-term adaptation, revealed that the unusually stable PSs structure provided the basis for the ephemerals to carry out high photosynthetic performances. It is proposed that the characteristic photosynthetic performances of ephemerals were resulted from effects of the long-term adaptation to the harsh environments.

Proteomic analysis and candidate allergenic proteins in Populus deltoides CL. "2KEN8" mature pollen.

Proteomic analysis was used to generate a map of Populus deltoides CL. "2KEN8" mature pollen proteins. By applying 2-D electrophoresis, we resolved 403 protein spots from mature pollen. Using the matrix-assisted laser desorption/ionization time time-of-flight/time-of-flight tandem mass spectrometry method, we identified 178 distinct proteins from 218 protein spots expressed in mature pollen. Moreover, out of these, 28 proteins were identified as putative allergens. The expression patterns of these putative allergen genes indicate that several of these genes are highly expressed in pollen. In addition, the members of profilin allergen family were analyzed and their expression patterns were compared with their homologous genes in Arabidopsis and rice. Knowledge of these identified allergens has the potential to improve specific diagnosis and allergen immunotherapy treatment for patients with poplar pollen allergy.