In dense canopy, a reduction in red to far-red (R/FR) light ratio triggers shade avoidance responses (SARs) in Arabidopsis thaliana, a shade avoiding plant. Two red/far-red (R/FR) light photoreceptors, PHYB and PHYA, were reported to be key negative regulators of the SARs. PHYB represses the SARs under normal light conditions; however, the role of PHYA in the SARs remains elusive. We set up two shade conditions: Shade and strong Shade (s-Shade) with different R/FR ratios (0.7 and 0.1), which allowed us to observe phenotypes dominated by PHYB-and PHYA-mediated pathway, respectively. By comparing the hypocotyl growth under these two conditions with time, we found PHYA was predominantly activated in the s-Shade after prolonged shade treatment. We further showed that under s-Shade, PHYA inhibits hypocotyl elongation partially through repressing the brassinosteroid (BR) pathway. COP1 and PIF4,5 act downstream of PHYA. After prolonged shade treatment, the nuclear localization of COP1 was reduced, while the PIF4 protein level was much lower in the s-Shade than that in Shade. Both changes occurred in a PHYA-dependent manner. We propose that under deep canopy, the R/FR ratio is extremely low, which promotes the nuclear accumulation of PHYA. Activated PHYA reduces COP1 nuclear speckle, which may lead to changes of downstream targets, such as PIF4,5 and HY5. Together, these proteins regulate the BR pathway through modulating BES1/BZR1 and the expression of BR biosynthesis and BR target genes.

Based on how plants respond to shade, we typically classify them into two groups: shade avoiding and shade tolerance plants. Under vegetative shade, the shade avoiding species induce a series of shade avoidance responses (SARs) to outgrow their competitors, while the shade tolerance species induce shade tolerance responses (STRs) to increase their survival rates under dense canopy. The molecular mechanism underlying the SARs has been extensively studied using the shade avoiding model plant Arabidopsis thaliana, while little is known about STRs. In Aarabidopsis, there is a PHYA-mediated negative feedback regulation that suppresses exaggerated SARs. Recent studies revealed that in shade tolerance Cardamine hirsuta plants, a hyperactive PHYA was responsible for suppressing shade-induced elongation growth. We propose that similar signaling components may be used by shade avoiding and shade tolerance plants, and different phenotypic outputs may result from differential regulation or altered dynamic properties of these signaling components. In this review, we summarized the role of PHYA and its downstream components in shade responses, which may provide insights into understanding how both types of plants respond to shade.

Background: The impact of statin use on the survival of esophageal cancer patients remains unclear now. The aim of this study was to identify the relationship between statin use and the long-term survival of esophageal cancer patients. Methods: The PubMed, EMBASE, and Web of Science databases were searched up to August 20, 2022, for relevant studies. The endpoints included overall survival (OS), cancer-specific survival (CSS), recurrence-free survival, and hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) were pooled to assess the association between statin use and the prognosis of esophageal cancer patients. Subgroup analysis based on the pathological type (adenocarcinoma vs squamous cell carcinoma), dose of statin use and tumor stage (tumor-node-metastasis I–III vs IV) was further performed. All statistical analyses were conducted using STATA 12.0 software. Results: A total of 7 retrospective studies involving 25,711 participants were included in this meta-analysis. The pooled results indicated that statin use was significantly associated with improved OS (HR = 0.80, 95% CI: 0.74–0.87, P < .001), CSS (HR = 0.77, 95% CI: 0.74–0.89, P < .001), and recurrence-free survival (HR = 0.38, 95% CI: 0.16–0.87, P = .022). Furthermore, subgroup analysis stratified by the pathological type, dose of statin use and tumor stage for OS and CSS showed similar results and indicated the protective role of statin use in the prognosis of esophageal cancer patients. Conclusion: Statin use is significantly associated with improved long-term survival of esophageal cancer patients and might serve as a promising prognostic indicator in esophageal cancer. However, more prospective high-quality studies are still needed to verify our findings.

Root hair development is regulated by hormonal and environmental cues, such as ethylene and low phosphate. Auxin efflux carrier PIN2 (PIN-FORMED 2) plays an important role in establishing a proper auxin gradient in root tips, which is required for root hair development. Ethylene promotes root hair development through increasing PIN2 abundance in root tips, which subsequently leads to enhanced expression of auxin reporter genes. However, how PIN2 is regulated remains obscure.Here, we report that Arabidopsis thaliana sav4 (shade avoidance 4) mutant exhibits defects in ethylene-induced root hair development and in establishing a proper auxin gradient in root tips.Ethylene treatment increased SAV4 abundance in root tips. SAV4 and PIN2 co-localize to the shootward plasma membrane (PM) of root tip epidermal cells. SAV4 directly interacts with the PIN2 hydrophilic region (PIN2HL) and regulates PIN2 abundance on the PM. Vacuolar degradation of PIN2 is suppressed by ethylene, which was weakened in sav4 mutant. Furthermore, SAV4 affects the formation of PIN2 clusters and its lateral diffusion on the PM.In summary, we identified SAV4 as a novel regulator of PIN2 that enhances PIN2 membrane clustering and stability through direct protein-protein interactions. Our study revealed a new layer of regulation on PIN2 dynamics.

Non-small cell lung cancer (NSCLC) is a malignant cancer worldwide. Long non-coding RNAs (lncRNAs) have emerged as key players in the development and progression of NSCLC, and may be potential biomarkers of NSCLC. Here, we investigated the clinical significance of lncRNA oxidative stress responsive serine rich 1 antisense RNA 1 (OSER1-AS1) in peripheral blood of patients with NSCLC. OSER1-AS1 in peripheral blood of patients with lung squamous cell carcinoma (LUSC), lung adenocarcinoma (LUAD), and healthy subjects was detected, and the clinical diagnostic efficacy was analyzed. The correlation between OSER1-AS1 expression and clinicopathological features in patients with LUSC and LUAD was analyzed. The downstream mechanism of OSER1-AS1 was explored. The area under the ROC curve of lncRNA OSER1-AS1 and miR-1298-5p/CHSY3 in LUSC and LUAD was compared using the MedCalc analysis. OSER1-AS1 was low in peripheral blood of patients with LUSC and LUAD. The area under the ROC curve for predicting LUSC was 0.800. The area under the ROC curve for predicting LUAD was 0.728. In LUSC and LUAD, OSER1-AS1 deficiency was associated with tumor node metastasis stage, lymph node metastasis, distal metastasis, and poor prognosis. miR-1298-5p was highly expressed, while chondroitin sulfate synthase 3 (CHSY3) was lowly expressed in patients with LUSC and LUAD. miR-1298-5p had target relations with OSER1-AS1 and CHSY3. lncRNA OSER1-AS1 had a higher diagnostic value in patients with NSCLC than miR-1298-5p and CHSY3. Overall, low expression of OSER1-AS1 in peripheral blood of NSCLC patients has high clinical significance, which provides a certain reference value for NSCLC early diagnosis.