A Novel Urine DNA Predictor for Noninvasive Early Diagnosis and Monitoring Minimal Residual Disease of Upper Tract Urothelial Carcinoma.

BACKGROUND: For early detection and postoperative monitoring of upper tract urothelial carcinoma (UTUC), the traditional detection method was limited to its invasiveness and insufficient sensitivity. We aim to use urine tumour DNA (utDNA) for detecting minimal residual disease (MRD), early diagnosis and perioperative monitoring in UTUC. METHOD: We previously established a utDNA multidimensional bioinformatic valuation model, named utLIFE, using low-coverage whole-genome sequencing and targeted deep sequencing. This prospective cohort enrolled 93 patients diagnosed with UTUC without metastasis. We collected morning urine samples on the day of surgery and the discharge day after the operation for utLIFE testing. In addition, we also enrolled 80 healthy controls to further validate the specificity of the utLIFE model in the study. RESULTS: The utLIFE of preoperative samples could discriminate UTUC with high specificity (96.25%, 77/80), and high sensitivity (96.77%, 90/93) regardless of stage and grade. The sensitivity of utLIFE was significantly higher than urine cytology (p < 0.001) and fluorescence in situ hybridisation (FISH) (p < 0.001) (N = 19), especially in early-stage and low-grade UTUC. Postoperative utLIFE scores were significantly decreased compared with those of preoperative samples (79 vs. 36, p < 0.001), indicating its association with tumour burden. For special pathology types, utLIFE performed less well in sensitivity and perioperative alteration. CONCLUSION: In conclusion, we established a bioinformatic utDNA valuation model, utLIFE, which was validated to be a rapid and noninvasive approach with high sensitivity for early detection and MRD monitoring for UTUC.

Phase 2 Study of Preoperative Tislelizumab in Combination with Low-dose Nab-Paclitaxel in Patients with Muscle-invasive Bladder Cancer.

BACKGROUND AND OBJECTIVE: Combinations of immune checkpoint inhibitors and nab-paclitaxel have achieved significant therapeutic effects in the treatment of advanced urothelial carcinoma. Our aim was to assess the efficacy and safety of tislelizumab combined with low-dose nab-paclitaxel in patients with muscle-invasive bladder cancer (MIBC). METHODS: TRUCE-01 was a single-arm phase 2 study that included 62 patients with T2-4a N0/X M0 MIBC tumors with predominant urothelial carcinoma histology. Eligible patients received three 21-d cycles of intravenous 200 mg tislelizumab on day 1 plus intravenous 200 mg nab-paclitaxel on day 2, followed by surgical assessment. The primary study endpoint was a clinical complete response (cCR). Treatment-related adverse event (TRAE) profiles were recorded according to Common Terminology Criteria for Adverse Events version 5.0. KEY FINDINGS AND LIMITATIONS: The safety analysis included all 62 patients and the efficacy analysis included 48 patients. The primary efficacy endpoint (cCR) was met by 25 patients (52%) patients. Among the 62 patients in the safety analysis, six (9.7%) had grade ≥3 TRAEs. CONCLUSIONS: Tislelizumab combined with low-dose nab-paclitaxel showed promising antitumor effectiveness and was generally well tolerated, which makes it an excellent preoperative therapy option for MIBC. PATIENT SUMMARY: We found that a combination of the drugs tislelizumab and low-dose nab-paclitaxel had satisfactory efficacy and safety for preoperative treatment of muscle-invasive bladder cancer.

Clinical effectiveness of a multitarget urine DNA test for urothelial carcinoma detection: a double-blinded, multicenter, prospective trial.

Urine-based testing is promising for noninvasive diagnosis of urothelial carcinoma (UC) but has suboptimal sensitivity for early-stage tumors. Herein, we developed a multitarget urine tumor DNA test, UI-Seek, for UC detection and evaluated its clinical feasibility. The prediction model was developed in a retrospective cohort (n = 382), integrating assays for FGFR3 and TERT mutations and aberrant ONECUT2 and VIM methylation to generate a UC-score. The test performance was validated in a double-blinded, multicenter, prospective trial (n = 947; ChiCTR2300076543) and demonstrated a sensitivity of 91.37% and a specificity of 95.09%. The sensitivity reached 75.81% for low-grade Ta tumors and exceeded 93% in high-grade Ta and higher stages (T1 to T4). Simultaneous identification of both bladder and upper urinary tract tumors was enabled with sensitivities exceeding 90%. No significant confounding effects were observed regarding benign urological diseases or non-UC malignancies. The test showed improved sensitivities over urine cytology, the NMP22 test, and UroVysion FISH alongside comparable specificities. The single-target accuracy was greater than 98% as confirmed by Sanger sequencing. Post-surgery UC-score decreased in 97.7% of subjects. Overall, UI-Seek demonstrated robust performance and considerable potential for the early detection of UC.

Analysis of the Genetic Characteristics and Metastatic Pathways of G1 and G2 Colorectal Neuroendocrine Neoplasms.

Objective: G1 and G2 colorectal neuroendocrine neoplasms (NENs) are a group of rare and indolent diseases. We aimed to delineate their genetic characteristics and explore their metastatic mechanisms. Methods: We used next-generation sequencing technology for targeted sequencing for 54 patients with G1 and G2 colorectal NENs. We delineated their genetic features and compared the genetic characteristics between metastatic NENs and nonmetastatic NENs. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was utilized to explore their abnormal pathways and study their potential metastatic mechanisms. Results: We collected 23 metastatic NENs and 31 nonmetastatic NENs. In the whole cohort, the common mutated genes were NCOR2, BRD4, MDC1, ARID1A, AXIN2, etc. The common copy number variations (CNVs) included amplification of HIST1H3D, amplification of HIST1H3E, and loss of PTEN. The KEGG enrichment analysis revealed that PI3K-Akt, MAPK, and Rap1 were the major abnormal pathways. There were significantly different genetic features between metastatic NENs and nonmetastatic NENs. The metastatic NENs shared only 47 (22.5%) mutated genes and 6 (13.3%) CNVs with nonmetastatic NENs. NCOR2, BRD4, CDKN1B, CYP3A5, and EIF1AX were the commonly mutated genes in metastatic NENs, while NCOR2, MDC1, AXIN2, PIK3C2G, and PTPRT were the commonly mutated genes in nonmetastatic NENs. Metastatic NENs presented a significantly higher proportion of abnormal pathways of cell senescence (56.5% vs 25.8%, P = .022) and lysine degradation (43.5% vs 16.1%, P = .027) than nonmetastatic NENs. Conclusion: G1 and G2 colorectal NENs are a group of heterogeneous diseases that might obtain an increased invasive ability through aberrant cell senescence and lysine degradation pathways.

The correlation between clinical outcomes and genomic analysis with high risk factors for the progression of osteosarcoma.

Osteosarcoma (OS) is a rare but aggressive malignancy. Despite previous reports, molecular characterization of this disease is not well understood, and little is known regarding OS in Chinese patients. Herein, we analyzed the genomic signatures of 73 Chinese OS cases. TP53, NCOR1, LRP1B, ATRX, RB1, and TFE3 were the most frequently mutated gene in our OS cohort. In addition, the genomic analysis of Western OS patients was performed. Notably, there were remarkable disparities in mutational landscape, base substitution pattern, and tumor mutational burden between the Chinese and Western OS cohorts. Specific molecular mechanisms, including DNA damage repair (DDR) gene mutations, copy number variation (CNV) presence, aneuploidy, and intratumoral heterogeneity, were associated with disease progression. Additionally, 30.1% of OS patients carried clinically actionable alterations, which were mainly enriched in PI3K, MAPK, DDR, and RTK signaling pathways. A specific molecular subtype incorporating DDR alterations and CNVs was significantly correlated with distant metastasis-free survival and event-free survival, and this correlation was observed in all subgroups with different characteristics. These findings comprehensively elucidated the genomic profile and revealed novel prognostic factors in OS, which would contribute to understanding this disease and promoting precision medicine of this population.

Case Report: A novel TP53 mutation in a patient with quadruple wild-type gastrointestinal stromal tumor.

In this report, we present a case study of a 64-year-old female who was diagnosed with gastrointestinal stromal tumors (GISTs) and subsequently developed liver metastases despite undergoing radical resection. Next-generation sequencing (NGS) assays indicated that the tumor lacked KIT/PDGFRA/SDH/RAS-P (RAS pathways, RAS-P) mutations, thereby classifying this patient as quadruple WT GIST (qGIST). Treatment with imatinib was initiated, and after 2.5 months, recurrence of the tumor and multiple metastases around the surgical site were observed. Consequently, the patient was switched to sunitinib treatment and responded well. Although she responded well to sunitinib, the patient died of tumor dissemination within 4 months. This case study highlights the potential efficacy of imatinib and the VEGFR-TKI sunitinib in treating qGIST patients harboring a TP53 missense mutation.

Mutation patterns and evolutionary action score of TP53 enable identification of a patient population with poor prognosis in advanced non-small cell lung cancer.

BACKGROUND: TP53 mutations are frequent in non-small cell lung cancer (NSCLC). Different categories of TP53 mutations may be associated with survival in advanced NSCLC, but their effect on prognosis is diverse. To date, a comprehensive comparison of the relationship between different classes of TP53 alterations and survival in advanced NSCLC has rarely been performed. Moreover, the prognostic significance of a novel approach called the evolutionary action of TP53 (EAp53) in advanced NSCLC is unclear. METHODS: A total of 210 patients with NSCLC harboring TP53 mutation data were enrolled. Genomic and clinical data for the Memorial Sloan Kettering Cancer Center (MSKCC) cohort with advanced NSCLC were obtained from cBioPortal. Relationship between clinical characteristics and TP53 mutations was performed by Fisher's exact test or χ2 test. Overall survival (OS) analysis was evaluated using Kaplan-Meier method and Cox proportional hazards regression model. RESULTS: TP53 mutations were identified in 51.4% of NSCLC patients and were mainly located in exons 5, 7, and 8. The distribution patterns of missense and truncating mutations of TP53 were remarkably different. Among patients with advanced NSCLC who never received immune checkpoint inhibitor treatments, EAp53 high-risk mutations were significantly associated with poor OS in both our cohort and the MSKCC cohort. Moreover, marked differences were observed in the mutational landscape between patients with EAp53 high-risk mutations (HR group) and other patients (OT group). The HR group displayed higher mutation frequencies in the RTK, cell cycle, and DNA damage repair (DDR) pathways than the OT group. In addition, the tumor mutation burden in the HR group was significantly higher than that in the OT group. CONCLUSIONS: This study provided important insights into the molecular-clinical profile of TP53-mutated NSCLC patients. Moreover, the data revealed that EAp53 high-risk mutations were an independent prognostic factor for worse OS in advanced NSCLC.

Comprehensive Molecular Profiling of Colorectal Cancer With Situs Inversus Totalis by Next-Generation Sequencing.

Background: Colorectal cancer (CRC) is one of the most prevalent malignances worldwide. However, CRC with situs inversus totalis (SCRC) is extremely rare, and molecular characterization of this disease has never been investigated. Methods: Tumor tissue samples from 8 patients with SCRC and 33 CRC patients without situs inversus totalis (NSCRC) were subjected to multigene next-generation sequencing. Results: The most frequently mutated genes in SCRC were APC, TP53, CHEK2, MDC1, GNAQ, KRAS, and SMAD4. A high frequency of SCRC tumors had mutations in DNA damage repair genes. Single amino acid substitutions in the DNA damage repair genes caused by continuous double base substitution was identified in the majority of this population. Furthermore, mutational profiles showed notable differences between the SCRC and NSCRC groups. In particular, CHEK2, MDC1, GNAQ, SMAD4, BRCA1, HLA-B, LATS2, and NLRC5 mutations were more frequently observed in SCRC patients. The mutation loci distributions of KRAS in the SCRC cohort differed from that of the NSCRC cohort. Additionally, differences in the targeted genomic profiles and base substitution patterns were observed between the two groups. Conclusions: These findings comprehensively revealed a molecular characterization of SCRC, which will contribute to the development of personalized therapy and improved clinical management of SCRC patients.

Molecular profiling and identification of prognostic factors in Chinese patients with small bowel adenocarcinoma.

Small bowel adenocarcinoma (SBA) is a rare malignancy with a poor prognosis and limited treatment options. Despite prior studies, molecular characterization of this disease is not well defined, and little is known regarding Chinese SBA patients. In this study, we conducted multigene next-generation sequencing and 16S ribosomal RNA gene sequencing on samples from 76 Chinese patients with surgically resected primary SBA. Compared with colorectal cancer and Western SBA cohorts, a distinctive genomic profile was revealed in Chinese SBA cohorts. According to the levels of clinical actionability to targetable alterations stratified by OncoKB system, 75% of patients harbored targetable alterations, of which ERBB2, BRCA1/2, and C-KIT mutations were the most common targets of highest-level actionable alterations. In DNA mismatch repair-proficient (pMMR) patients, significant associations between high tumor mutational burden and specific genetic alterations were identified. Moreover, KRAS mutations/TP53 wild-type/nondisruptive mutations (KRASmut /TP53wt/non-dis ) were independently associated with an inferior recurrence-free survival (hazard ratio [HR] = 4.21, 95% confidence interval [CI] = 1.94-9.14, P < .001). The bacterial profile revealed Proteobacteia, Actinobacteria, Firmicutes, Bacteroidetes, Fusobacteria, and Cyanobacteria were the most common phyla in SBA. Furthermore, patients were clustered into three subgroups based on the relative abundance of bacterial phyla, and the distributions of the subgroups were significantly associated with the risk of recurrence stratified by TP53 and KRAS mutations. In conclusion, these findings provided a comprehensive molecular basis for understanding SBA, which will be of great significance in improving the treatment strategies and clinical management of this population.

Molecular Identification and Genetic Characterization of Early-Stage Multiple Primary Lung Cancer by Large-Panel Next-Generation Sequencing Analysis.

OBJECTIVE: The incidence of early stage multiple primary lung cancer (MPLC) has been increasing in recent years, while the ideal strategy for its diagnosis and treatment remains controversial. The present study conducted genomic analysis to identify a new molecular classification method for accurately predicting the diagnosis and therapy for patients with early stage MPLC. METHODS: A total of 240 tissue samples from 203 patients with multiple-non-small-cell lung cancers (NSCLCs) (n = 30), early stage single-NSCLC (Group A, n = 94), and advanced-stage NSCLC (Group B, n = 79) were subjected to targeted multigene panel sequencing. RESULTS: Thirty patients for whom next-generation sequencing was performed on >1 tumor were identified, yielding 45 tumor pairs. The frequencies of EGFR, TP53, RBM10, ERBB2, and CDKN2A mutations exhibited significant differences between early and advanced-stage NSCLCs. The prevalence of the EGFR L858R mutation in early stage NSCLC was remarkably higher than that in advanced-stage NSCLC (P = 0.047). The molecular method classified tumor pairs into 26 definite MPLC tumors and four intrapulmonary metastasis (IM) tumors. A high rate of discordance in driver genetic alterations was found in the different tumor lesions of MPLC patients. The prospective Martini histologic prediction of MPLC was discordant with the molecular method for three patients (16.7%), particularly in the prediction of IM (91.7% discordant). CONCLUSIONS: Comprehensive molecular evaluation allows the unambiguous delineation of clonal relationships among tumors. In comparison, the Martini and Melamed criteria have notable limitations in the recognition of IM. Our results support the adoption of a large panel to supplement histology for strongly discriminating NSCLC clonal relationships in clinical practice.

Comparative genomic signatures in young and old Chinese patients with colorectal cancer.

BACKGROUND: Occurrence at a young age is known to be associated with unique clinical features in colorectal cancer (CRC). However, the genomic differences between young and old patients with CRC are not well elucidated and, to the best of our knowledge, have never been investigated in a Chinese population. METHODS: Tumor tissue samples from 29 young (age ≤50 years) and 46 old (age >50 years) patients with CRC were collected. Targeted sequencing of 808 cancer-related genes was conducted to characterize the genomic landscape for Chinese CRC. RESULTS: Overall, mutational profiles exhibited notable differences between the two groups. In particular, APC and PIK3CA mutations were more frequently observed in old patients (p = 0.009 and p = 0.012, respectively), while SMAD4 mutations tended to occur in young patients (p = 0.054). Mutation loci distributions of KRAS in the young cohort differed from those in the old cohort, and a higher frequency of KRAS codon 12 mutations was potentially associated with a young age (p = 0.076). The frequencies of clinically actionable alterations were analyzed by defined age categories, which unveiled a distinctive targeted genomic profile in the young group. Furthermore, among patients with mismatch repair-proficient (pMMR) CRC, tumor mutation burden (TMB) was positively correlated with age (Pearson's r = 0.306, p = 0.011), and genomic alterations associated with high TMB in young patients differentiated from those in old patients. CONCLUSIONS: These findings revealed different molecular characterization between young and old Chinese patients with CRC, which may provide novel insights for the personalized treatment of CRC.

Comprehensive analysis of genomic alterations detected by next-generation sequencing-based tissue and circulating tumor DNA assays in Chinese patients with non-small cell lung cancer.

While tumor genotyping is the standard treatment for patients with non-small cell lung cancer (NSCLC), spatial and temporal tumor heterogeneity and insufficient specimens can lead to limitations in the use of tissue-based sequencing. Circulating tumor DNA (ctDNA) fully encompasses tumor-specific sequence alterations and offers an alternative to tissue sample biopsies. However, few studies have evaluated whether the frequency of multiple genomic alterations observed following ctDNA sequencing is similar to that observed following tissue sequencing in NSCLC. Therefore, in the present study, targeted next-generation sequencing (NGS) was performed on tissue and plasma ctDNA samples in 99 patients with NSCLC. Overall, the frequencies of genetic alterations detected in ctDNA were positively correlated with those detected via tissue profiling (r=0.812; P=0.022). Genomic data revealed significant mutual exclusivity between alterations in epidermal growth factor receptor (EGFR) and tumor protein 53 (TP53; P=0.020), and between alterations in EGFR and KRAS (P=0.008), as well as potential mutual exclusivity between alterations in EGFR and Erb-B2 receptor tyrosine kinase 2 (P=0.059). Furthermore, the EGFR mutant allele frequency (MAF) was positively correlated with the TP53 MAF in individual tumors (r=0.773; P=0.005), and there was a marked difference in the EGFR MAF between patients with and without the TP53 mutation (P=0.001). Levels of the tumor serum marker CA242 in patients with ctDNA-detectable mutations were higher compared with those in patients without ctDNA-detectable mutations. The data from the present study highlight the importance of tissue and plasma ctDNA screening by NGS to guide personalized therapy and promote the clinical management of patients with NSCLC.

Molecular and clinical analysis of Chinese patients with anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer.

Anaplastic lymphoma kinase (ALK) fusions have been recognized as a therapeutic target in non-small cell lung cancer (NSCLC). However, molecular signatures and clinical characteristics of the Chinese population with ALK-rearranged NSCLC are not well elucidated. In the present study, we carried out targeted next-generation sequencing on tissue and plasma ctDNA samples in 1688 patients with NSCLC. Overall, ALK fusions were detected in 70 patients (4.1%), and the frequencies of ALK fusions detected in tissue and plasma samples were 5.1% and 3.3%, respectively. Additionally, the prevalence of breakpoint locations for EML4-ALK fusions in ctDNA was significantly correlated with that in tumor tissues (R2  = .91, P = .045). According to age, the incidence rates of ALK fusions among young (age <45 years), middle-aged (between 45 and 70 years) and elderly (>70 years) patients were significantly different (P < .001). In 70 ALK-rearranged cases, coexistence of epidermal growth factor receptor (EGFR) alterations and ALK fusions was detected in 12 cases (17.1%) and EGFR mutations tended to coexist with non-EML4-ALK rearrangements. Notably, novel ALK fusion partners, including TRIM66, SWAP70, WNK3, ERC1, TCF12 and FBN1 were identified in the present study. Among EML4-ALK fusion variants, patients with variant V1 were younger than patients with variant V3 (P = .023), and TP53 mutations were more frequently concurrent with variant V3 compared with variant V1 (P = .009). In conclusion, these findings provide new insights into the molecular-clinical profiles of patients with ALK-rearranged NSCLC that may improve the treatment strategy of this population.

iTRAQ-based proteomics analysis of autophagy-mediated immune responses against the vascular fungal pathogen Verticillium dahliae in Arabidopsis.

The mechanisms underlying the functional link between autophagy and plant innate immunity remain largely unknown. In this study, we investigated the autophagy-mediated plant defense responses against Verticillium dahliae (V. dahliae) infection by comparative proteomics and cellular analyses. An assessment of the autophagy activity and disease development showed that autophagic processes were tightly related to the tolerance of Arabidopsis plant to Verticillium wilt. An isobaric tags for relative and absolute quantification (iTRAQ)-based proteomics analysis was performed, and we identified a total of 780 differentially accumulated proteins (DAPs) between wild-type and mutant atg10-1 Arabidopsis plants upon V. dahliae infection, of which, 193 ATG8-family-interacting proteins were identified in silico and their associations with autophagy were verified for several selected proteins. Three important aspects of autophagy-mediated defense against V. dahliae infection were revealed: 1) autophagy is required for the activation of upstream defense responses; 2) autophagy-mediated mitochondrial degradation (mitophagy) occurs and is an important player in the defense process; and 3) autophagy promotes the transdifferentiation of perivascular cells and the formation of xylem hyperplasia, which are crucial for protection against this vascular disease. Together, our results provide several novel insights for understanding the functional association between autophagy and plant immune responses.

The cotton MYB108 forms a positive feedback regulation loop with CML11 and participates in the defense response against Verticillium dahliae infection.

Accumulating evidence indicates that plant MYB transcription factors participate in defense against pathogen attack, but their regulatory targets and related signaling processes remain largely unknown. Here, we identified a defense-related MYB gene (GhMYB108) from upland cotton (Gossypium hirsutum) and characterized its functional mechanism. Expression of GhMYB108 in cotton plants was induced by Verticillium dahliae infection and responded to the application of defense signaling molecules, including salicylic acid, jasmonic acid, and ethylene. Knockdown of GhMYB108 expression led to increased susceptibility of cotton plants to V. dahliae, while ecotopic overexpression of GhMYB108 in Arabidopsis thaliana conferred enhanced tolerance to the pathogen. Further analysis demonstrated that GhMYB108 interacted with the calmodulin-like protein GhCML11, and the two proteins form a positive feedback loop to enhance the transcription of GhCML11 in a calcium-dependent manner. Verticillium dahliae infection stimulated Ca(2+) influx into the cytosol in cotton root cells, but this response was disrupted in both GhCML11-silenced plants and GhMYB108-silenced plants in which expression of several calcium signaling-related genes was down-regulated. Taken together, these results indicate that GhMYB108 acts as a positive regulator in defense against V. dahliae infection by interacting with GhCML11. Furthermore, the data also revealed the important roles and synergetic regulation of MYB transcription factor, Ca(2+), and calmodulin in plant immune responses.

Robustly photogenerating H2 in water using FeP/CdS catalyst under solar irradiation.

Photosplitting water for H2 production is a promising, sustainable approach for solar-to-chemical energy conversion. However, developing low-cost, high efficient and stable photocatalysts remains the major challenge. Here we report a composite photocatalyst consisting of FeP nanoparticles and CdS nanocrystals (FeP/CdS) for photogenerating H2 in aqueous lactic acid solution under visible light irradiation. Experimental results demonstrate that the photocatalyst is highly active with a H2-evolution rate of 202000 µmol h(-1) g(-1) for the first 5 h (106000 µmol h(-1) g(-1) under natural solar irradiation), which is the best H2 evolution activity, even 3-fold higher than the control in situ photo-deposited Pt/CdS system, and the corresponding to an apparent quantum efficiency of over 35% at 520 nm. More important, we found that the system exhibited excellent stability and remained effective after more than 100 h in optimal conditions under visible light irradiation. A wide-ranging analysis verified that FeP effectively separates the photoexcited charge from CdS and showed that the dual active sites in FeP enhance the activity of FeP/CdS photocatalysts.

Cotton major latex protein 28 functions as a positive regulator of the ethylene responsive factor 6 in defense against Verticillium dahliae.

In this study, we identified a defense-related major latex protein (MLP) from upland cotton (designated GhMLP28) and investigated its functional mechanism. GhMLP28 transcripts were ubiquitously present in cotton plants, with higher accumulation in the root. Expression of the GhMLP28 gene was induced by Verticillium dahliae inoculation and was responsive to defense signaling molecules, including ethylene, jasmonic acid, and salicylic acid. Knockdown of GhMLP28 expression by virus-induced gene silencing resulted in increased susceptibility of cotton plants to V. dahliae infection, while ectopic overexpression of GhMLP28 in tobacco improved the disease tolerance of the transgenic plants. Further analysis revealed that GhMLP28 interacted with cotton ethylene response factor 6 (GhERF6) and facilitated the binding of GhERF6 to GCC-box element. Transient expression assay demonstrated that GhMLP28 enhanced the transcription factor activity of GhERF6, which led to the augmented expression of some GCC-box genes. GhMLP28 proteins were located in both the nucleus and cytoplasm and their nuclear distribution was dependent on the presence of GhERF6. Collectively, these results demonstrate that GhMLP28 acts as a positive regulator of GhERF6, and synergetic actions of the two proteins may contribute substantially to protection against V. dahliae infection in cotton plants.

The cotton transcription factor TCP14 functions in auxin-mediated epidermal cell differentiation and elongation.

Plant-specific TEOSINTE-BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factors play crucial roles in development, but their functional mechanisms remain largely unknown. Here, we characterized the cellular functions of the class I TCP transcription factor GhTCP14 from upland cotton (Gossypium hirsutum). GhTCP14 is expressed predominantly in fiber cells, especially at the initiation and elongation stages of development, and its expression increased in response to exogenous auxin. Induced heterologous overexpression of GhTCP14 in Arabidopsis (Arabidopsis thaliana) enhanced initiation and elongation of trichomes and root hairs. In addition, root gravitropism was severely affected, similar to mutant of the auxin efflux carrier PIN-FORMED2 (PIN2) gene. Examination of auxin distribution in GhTCP14-expressing Arabidopsis by observation of auxin-responsive reporters revealed substantial alterations in auxin distribution in sepal trichomes and root cortical regions. Consistent with these changes, expression of the auxin uptake carrier AUXIN1 (AUX1) was up-regulated and PIN2 expression was down-regulated in the GhTCP14-expressing plants. The association of GhTCP14 with auxin responses was also evidenced by the enhanced expression of auxin response gene IAA3, a gene in the AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) family. Electrophoretic mobility shift assays showed that GhTCP14 bound the promoters of PIN2, IAA3, and AUX1, and transactivation assays indicated that GhTCP14 had transcription activation activity. Taken together, these results demonstrate that GhTCP14 is a dual-function transcription factor able to positively or negatively regulate expression of auxin response and transporter genes, thus potentially acting as a crucial regulator in auxin-mediated differentiation and elongation of cotton fiber cells.