Response and inversion of skewness parameters to meteorological factors based on RGB model of leaf color digital image.

In the natural environment, complex and changeable meteorological factors can influence changes in the internal physiology and phenotype of crops. It is important to learn how to convert complex meteorological factor stimuli into plant perception phenotypes when analyzing the biological data obtained under the natural field condition. We restored the true gradation distribution of leaf color, which is also known as the skewed distribution of color scale, and obtained 20 multi-dimensional color gradation skewness-distribution (CGSD) parameters based on the leaf color skewness parameter system. Furthermore, we analyzed the correlation between the five corresponding meteorological factors and canopy CGSD parameters of peppers growing in a greenhouse and cabbages growing in an open air environment, built response model and inversion mode of leaf color to meteorological factors. Based on the analysis, we find a new method for correlating complex environmental problems with multi-dimensional parameters. This study provides a new idea for building a correlation model that uses leaf color as a bridge between meteorological factors and plants internal physiological state.

Thioredoxins m regulate plastid glucose-6-phosphate dehydrogenase activity in Arabidopsis roots under salt stress.

Plants contain several NADPH-producing enzymes including glucose-6-phosphate dehydrogenases (G6PDH) with different sub-cellular localizations. The activity of plastidial G6PDHs is redox-regulated by thioredoxins (TRX). Although specific TRXs are known to regulate chloroplastic isoforms of G6PDH, little information is available for plastidic isoforms found in heterotrophic organs or tissues. Here, we investigated TRX regulation of the two G6PDH plastidic isoforms of Arabidopsis roots during exposure to a mild salt stress. We report that in vitro m-type TRXs are the most efficient regulators of the G6PDH2 and G6PDH3 mainly found in Arabidopsis roots. While expression of the corresponding G6PD and plastidic TRX genes was marginally affected by salt, it impaired root growth of several of the corresponding mutant lines. Using an in situ assay for G6PDH, G6PDH2 was found to be the major contributor to salt-induced increases in activity, while data from ROS assays further provide in vivo evidence that TRX m acts in redox regulation during salt stress. Taken together, our data suggest that regulation of plastid G6PDH activity by TRX m may be an important player regulating NADPH production in Arabidopsis roots undergoing salt stress.

Skewed distribution of leaf color RGB model and application of skewed parameters in leaf color description model.

BACKGROUND: Image processing techniques have been widely used in the analysis of leaf characteristics. Earlier techniques for processing digital RGB color images of plant leaves had several drawbacks, such as inadequate de-noising, and adopting normal-probability statistical estimation models which have few parameters and limited applicability. RESULTS: We confirmed the skewness distribution characteristics of the red, green, blue and grayscale channels of the images of tobacco leaves. Twenty skewed-distribution parameters were computed including the mean, median, mode, skewness, and kurtosis. We used the mean parameter to establish a stepwise regression model that is similar to earlier models. Other models based on the median and the skewness parameters led to accurate RGB-based description and prediction, as well as better fitting of the SPAD value. More parameters improved the accuracy of RGB model description and prediction, and extended its application range. Indeed, the skewed-distribution parameters can describe changes of the leaf color depth and homogeneity. CONCLUSIONS: The color histogram of the blade images follows a skewed distribution, whose parameters greatly enrich the RGB model and can describe changes in leaf color depth and homogeneity.

CT combined with tumor markers in the diagnosis and prognosis of hepatocellular carcinoma.

PURPOSE: To investigate the application values of CT combined with tumor markers (TM) in the diagnosis and prognosis of hepatocellular carcinoma (HCC). METHODS: 62 HCC patients were selected as the study group and all of them had undergone hepatectomy. In addition, 40 healthy subjects composed the control group. Blood samples were collected preoperatively from the subjects of the study group, and serum alpha fetoprotein (AFP), carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) levels were determined by radioimmunoassay. The correlation between serum TM levels and clinicopathological features was investigated by pathological examination. The imaging features of HCC were explored by spiral CT plain scanning and enhanced scanning. The diagnostic efficiency of single detection of TM, combined detection of TMs and combined detection of TMs and CT was analyzed by receiver operating characteristic (ROC). RESULTS: The levels of serum AFP, CA19-9 and CEA in HCC patients were significantly higher than those in the control group (p<0.05). Patients with low differentiation and distant metastasis had higher levels of AFP, CA19-9 and CEA (p<0.05) compared with patients with high differentiation and no distant metastasis. There were no significant differences in TM levels in HCC patients with different age, gender and clinical stages (p>0.05). The ROC analysis showed that the single detection of serum AFP, CEA or CA19-9 had lower specificity and sensitivity compared with the combined detection of the three TMs (p<0.05). The combined CT examination could achieve a specificity of 95.71% and a sensitivity of 87.47%, superior to the combined detection of the TMs (p<0.05). Eight HCC patients relapsed within 6 months after operation. Compared with those before operation, the levels of serum AFP, CA19-9 and CEA in the relapsed patients were increased significantly, and the TM levels were higher than those in patients without relapse (p<0.05). CONCLUSIONS: The detection of serum AFP, CA19-9 and CEA combined with CT can overcome the deficiency of single detection, avoid misdiagnosis and missed diagnosis, and increase significantly the positive detection rate of HCC.

Multi-slice spiral CT evaluation of breast cancer chemotherapy and correlation between CT results and breast cancerspecific gene 1.

PURPOSE: To investigate multi-slice spiral CT (MSCT) imaging with breast cancer chemotherapy and the correlation between MSCT and breast cancer-specific gene 1 (BCSG1). METHODS: 86 patients with breast cancer were enrolled from January 2016 to May 2017. All of them were treated with neoadjuvant chemotherapy, and underwent MSCT scan before and after treatment to evaluate the efficacy of chemotherapy. The expression of BCSG1 in tumor tissue was detected by immunohistochemistry and the correlation between CT results and BCSG1 was analyzed. RESULTS: MSCT evaluation of the efficacy of chemotherapy in breast cancer patients was consistent with pathological evaluation (p<0.05). MSCT in patients after chemotherapy was significantly better than before chemotherapy (p<0.05). CT examination showed that tumor diameter and lymph node size were significantly reduced after chemotherapy (p<0.05). The positive rates of BCSG1 in patients with different TNM stages after chemotherapy were significantly decreased (p<0.05) and the CT perfusion value of BCSG1 in the low expression group was significantly higher than in the high expression group (p<0.05). CONCLUSIONS: MSCT can accurately evaluate the effect of chemotherapy in breast cancer. The results of MSCT were closely related to the expression of BCSG1, which may provide a reference for predicting the effect of chemotherapy in breast cancer which could have important clinical significance.

The mitogen-activated protein kinase cascade MKK1-MPK4 mediates salt signaling in rice.

Mitogen-activated protein kinase (MAPK) pathways have been implicated in signal transduction of both biotic and abiotic stresses in plants. In this study, we found that the transcript of a rice (Oryza sativa) MAPKK (OsMKK1) was markedly increased by salt stress. By examining the survival rate and Na(+) content in shoot, we found that OsMKK1-knockout (osmkk1) mutant was more sensitive to salt stress than the wild type. OsMKK1 activity in the wild-type seedlings and protoplasts was increased by salt stress. Yeast two-hybrid and in vitro and in vivo kinase assays revealed that OsMKK1 targeted OsMPK4. OsMPK4 activity was increased by salt, which was impaired in osmkk1 plants. In contrast, overexpression of OsMKK1 increased OsMPK4 activity in protoplasts. By comparing the transcription factors levels between WT and osmkk1 mutant, OsMKK1 was necessary for salt-induced increase in OsDREB2B and OsMYBS3. Taken together, the data suggest that OsMKK1 and OsMPK4 constitute a signaling pathway that regulates salt stress tolerance in rice.

Characterization and mapping of a salt-sensitive mutant in rice (Oryza sativa L.).

A salt-sensitive mutant designated rice salt sensitive 2 (rss2) was isolated from the M2 generation of the rice cultivar Nipponbare mutagenized with ethyl methanesulfonate (EMS). This mutant exhibited a greater decrease in salt tolerance with a significant increase in Na(+) content in its shoots. Genetic analysis indicated that the increase in Na(+) in rss2 was controlled by a single recessive gene. Further genome-wide analysis of the linkage map constructed from the F2 population of rss2/Zhaiyeqing 8 (ZYQ8) showed that two quantitative trait loci (QTLs) on chromosomes 1 and 6 were responsible for the Na(+) concentration in shoots, which explained 14.5% and 53.3%, respectively, of the phenotypic variance. The locus on chromosome 1, but not that on chromosome 6, was also detected in the F2 population of Nipponbare/ZYQ8, suggesting that the QTL on chromosome 6 was responsible for the salt sensitivity in rss2. By analyzing the recombination events in 220 mutant individuals of an enlarged mapping population of rss2/ZYQ8, the rss2 locus was precisely mapped to an interval of 605.3 kb between insertion/deletion (InDel) markers IM21962 and IM22567. This finding will facilitate the cloning of the rss2 locus and provide insight into the physiological mechanisms of salt sensitivity in rice.

Phosphatidic acid mediates salt stress response by regulation of MPK6 in Arabidopsis thaliana.

• Phospholipase D (PLD) hydrolyzes phospholipids to produce phosphatidic acid (PA) and a head group, and is involved in the response to various environmental stresses, including salinity. Here, we determined the roles of PLDα and PA in the mediation of salt (NaCl)-stress signaling through the regulation of mitogen-activated protein kinase (MAPK or MPK) in Arabidopsis thaliana. • NaCl-induced changes in the content and composition of PA were quantitatively profiled by electrospray ionization-tandem mass spectrometry (ESI-MS/MS). A specific PA species (a MAPK 16:0-18:2 PA), which was increased in abundance by exposure to NaCl, bound to a MPK6, according to filter binding and ELISA. The effect of PA on MPK6 activity was tested using in-gel analysis. • 16:0-18:2 PA stimulated the activity of MPK6 immunoprecipitated from Arabidopsis leaf extracts. Treatment with NaCl induced a transient activation of MPK6 in wild-type plant, but the activation was abolished in the pldα1 plant mutant. A plasma membrane Na(+)/H(+) antiporter (SOS1) was identified as a downstream target of MPK6. MPK6 phosphorylated the C-terminal fragment of SOS1. The MPK6 phosphorylation of SOS1 was stimulated by treatment with NaCl, as well as directly by PA. • These results suggest that PA plays a critical role in coupling MAPK cascades in response to salt stress.