Investigation of Salt Tolerance Mechanisms across a Root Developmental Gradient in Almond Rootstocks

The intensive use of groundwater in agriculture under the current climate conditions leads to acceleration of soil salinization. Given that almond is a salt-sensitive crop, selection of salt-tolerant rootstocks can help maintain productivity under salinity stress. Selection for tolerant rootstocks at an early growth stage can reduce the investment of time and resources. However, salinity-sensitive markers and salinity tolerance mechanisms of almond species to assist this selection process are largely unknown. We established a microscopy-based approach to investigate mechanisms of stress tolerance in and identified cellular, root anatomical, and molecular traits associated with rootstocks exhibiting salt tolerance. We characterized three almond rootstocks: Empyrean-1 (E1), Controller-5 (C5), and Krymsk-86 (K86). Based on cellular and molecular evidence, our results show that E1 has a higher capacity for salt exclusion by a combination of upregulating ion transporter expression and enhanced deposition of suberin and lignin in the root apoplastic barriers, exodermis, and endodermis, in response to salt stress. Expression analyses revealed differential regulation of cation transporters, stress signaling, and biopolymer synthesis genes in the different rootstocks. This foundational study reveals the mechanisms of salinity tolerance in almond rootstocks from cellular and structural perspectives across a root developmental gradient and provides insights for future screens targeting stress response

Sec23 Gene Members Differentially Contribute to Polarized Growth in \u3cem\u3ePhyscomitrella patens\u3c/em\u3e

Polarized secretion is essential for cell biological processes across the tree of life. In particular walled organisms, such as yeast, filamentous fungi, and plants use polarized secretion to divide and grow thereby providing excellent model systems to unravel the molecular mechanisms controlling this process. For polarized growth, an active secretory system is required to deliver specific building materials to the growth region. As part of the secretory pathway, transport from the endoplasmic reticulum (ER) to the Golgi apparatus, which is mediated by the coat protein complex II (COPII) is therefore a prerequisite for polarized secretion. I have investigated the role of COPII in the juvenile tissue of the moss Physcomitrella patens, which grows exclusively by polarized secretion. Interestingly in P. patens, small gene families encode each of the subunits of the COPII complex. To investigate whether these small gene families are redundant, I analyzed the loss of function phenotype resulting from silencing Sec23, a component of the inner coat of COPII, which is encoded by seven highly similar genes. To my surprise, I found that silencing Sec23D caused a severe growth defect, while silencing the remaining six Sec23 genes had no significant defect. Coding sequence complementation showed partial functional redundancy between only Sec23D and Sec23E, suggesting that Sec23D and to a limited extent Sec23E play pivotal roles during polarized secretion, I found that Sec23D localizes to the ER and partially overlaps with the Golgi. In addition, Sec23D heterodimerizes with two of the seven Sec24 genes in moss, suggesting that Sec23D is a canonical COPII component. To analyze the role of Sec23D and the remaining six Sec23 isoforms, I developed CRISPR-Cas9 mediated mutagenesis vector system for P. patens. This genomic editing method was shown to be more efficient than traditional homologous recombination. Using stable sec23 mutants, I found that the sec23d null mutants grow very slowly, have significant defects in ER morphology, and in secretion to the Golgi as well as to the plasma membrane. However, I observed that ∆sec23abcfg mutants grow similar to wild type, have no ER morphology defects, no secretion defects to the Golgi, and only a mild secretion defects to the plasma membrane. These data suggest that Sec23D is the dominant Sec23 subunit of the COPII complex, mediating the majority cargo transport and the specific cargo transport from the ER to the Golgi during polarized growth. Using CRISPR-Cas9 genome editing, I uncovered an interesting in-frame deletion mutant, sec23d∆AAL, which resembles the sec23d null mutant. Like the sec23d null mutant, sec23d∆AAL exhibits severe growth defects, altered ER morphology, and defects in secretion to the Golgi as well as to the plasma membrane. Imaging mRuby2 tagged sec23d∆AAL revealed that sec23d∆AAL is expressed but may not function like the wild type protein. To investigate how loss of these three residues impacts the function of Sec23D, I performed a directed yeast two-hybrid assay to demonstrate that the deletion mutant no longer binds Sec24C. To determine if this site is conserved in other organisms, I deleted the equivalent amino acids in budding yeast and human Sec23 proteins (ScSec23 and HsSec23A). In a yeast complementation assay, where the wild type copies of ScSec23 and HsSec23A rescue the yeast sec23-1 temperature sensitive mutant, I found that mutants in ScSec23 and HsSec23A harboring either deletion of the equivalent three amino acids or conversion of those amino acids to glycine were unable to rescue. These data suggest that these residues in the N-terminus of Sec23 are evolutionally conserved and allosterically regulate the interaction between Sec23 and Sec24

Selective chemical probes can untangle the complexity of the plant cell endomembrane system

The endomembrane system is critical for plant growth and development and understanding its function and regulation is of great interest for plant biology research. Small-molecule targeting distinctive endomembrane components have proven powerful tools to dissect membrane trafficking in plant cells. However, unambiguous elucidation of the complex and dynamic trafficking processes requires chemical probes with enhanced precision. Determination of the mechanism of action of a compound, which is facilitated by various chemoproteomic approaches, opens new avenues for the improvement of its specificity. Moreover, rational molecule design and reverse chemical genetics with the aid of virtual screening and artificial intelligence will enable us to discover highly precise chemical probes more efficiently. The next decade will witness the emergence of more such accurate tools, which together with advanced live quantitative imaging techniques of subcellular phenotypes, will deepen our insights into the plant endomembrane system

Exploring the cortical habituation in migraine patients based on contingent negative variation

IntroductionCognitive dysfunction has frequently been found in patients with migraine. The so-called contingent negative variation (CNV) and EEG power spectral densities may be the best choices to explore the underlining pathophysiology, such as cortical inhibition and habituation.MethodsThirty migraine patients without aura and healthy controls matched for sex, age, and education were recruited separately for CNV recording. The amplitudes, latencies, and squares of different CNV components, such as oCNV, iCNV, tCNV, and PINV, were selected and analyzed. Behavioral data, such as manual reaction time (RT), were analyzed. We used the Person correlation coefficient R to analyze different ERP components in relation to clinical characteristics. A multiple regression analysis was conducted for the migraine group. Spectral analysis of EEG data from all channels using the fast Fourier transform (FFT).ResultsThe migraine group had longer A-latency, C-latency, and iCNV-latency than the control group. The migraine group had higher iCNV-amplitude, oCNV-amplitude, and tCNV-amplitude than the control group, especially those located in the occipital area. The iCNV-square, oCNV-square, tCNV-square, or PINV-square in the migraine group was significantly larger than the control group. Different correlations were found between clinical characteristics and ERP components. The delta or theta activity in the migraine group was statistically lower than in the control group.DiscussionOur study has revealed that migraine attacks may influence responsivity, pre-activation, habituation, and cortical inhibition not only on the behavioral level but also on the electrophysiological level. Abnormal changes in cortical habituation and inhibition can be interpreted as CNV components. Additionally, analyses have revealed correlations between CNV components and various factors, including age, the clinical course of the condition, attack frequency, pain intensity, and duration. Thus, repetitive migraine attacks can lead to a reduction in cortical inhibition and subsequent impairment in executive function

Association of plasma apolipoprotein CIII, high sensitivity C-reactive protein and tumor necrosis factor-α contributes to the clinical features of coronary heart disease in Li and Han ethnic groups in China

Abstract Background Apolipoprotein CIII (apoCIII) is an independent risk for coronary heart disease (CHD). In this study, we investigated the associations among plasma apoCIII, hs-CRP and TNF-α levels and their roles in the clinical features of CHD in the Li and Han ethnic groups in China. Methods A cohort of 474 participants was recruited (238 atherosclerotic patients and 236 healthy controls) from the Li and Han ethnic groups. Blood samples were obtained to evaluate apoCIII, TNF-α, hs-CRP and lipid profiles. Chi-squared, t-tests, and Kruskal–Wallis or Wilcoxon–Mann–Whitney tests, Pearson or Spearman correlation tests and multiple unconditional logistic regression were employed to analyze lipid profiles and variations in plasma apoCIII, TNF-α, hs-CRP in subgroups of CHD and their contributions to CHD using SPSS version 20.0 software. Results Compared to healthy participants, unfavorable lipid profiles were identified in CHD patients with enhanced systolic pressure, diastolic pressure, fasting blood sugar (FBS), TG, TC, LDL-C, apoB, Lp(a) (P  0.05). Plasma apoCIII, TNF-α and hs-CRP contributed to the development of CHD (OR = 2.554, 7.252, 6.035, P < 0.01) with paired correlations in CHD patients (apoCIII vs. TNF-α, r = 0.425; apoCIII vs. hs-CRP, r = 0.319; TNF-α vs. hs-CRP, r = 0.400, P < 0.01). Conclusions Association among plasma apoCIII, hs-CRP and TNF-α interacts with unfavorable lipid profiles to contribute to the clinical features of CHD with stable angina, unstable angina, and AMI in the Li and Han ethnic groups in China

Cortical Reorganization After Optical Alignment in Strabismic Patients Outside of Critical Period

PURPOSE. To measure visual crowding, an essential bottleneck on object recognition and reliable psychophysical index of cortex organization, in older children and adults with horizontal concomitant strabismus before and after strabismus surgery. METHODS. Using real-time eye tracking to ensure gaze-contingent display, we examined the peripheral visual crowding effects in older children and adults with horizontal concomitant strabismus but without amblyopia before and after strabismus surgery. Patients were asked to discriminate the orientation of the central tumbling E target letter with flankers arranged along the radial or tangential axis in the nasal or temporal hemifield at different eccentricities (5 degrees or 10 degrees). The critical spacing value, which is the minimum space between the target and the flankers required for correct discrimination, was obtained for comparisons before and after strabismus surgery. RESULTS. Twelve individuals with exotropia (6 males, 21.75 +/- 7.29 years, mean +/- SD) and 15 individuals with esotropia (6 males, 24.13 +/- 5.96 years) participated in this study. We found that strabismic individuals showed significantly larger critical spacing with nasotemporal asymmetry along the radial axis that related to the strabismus pattern, with exotropes exhibiting stronger temporal field crowding and esotropes exhibiting stronger nasal field crowding before surgical alignment. After surgery, the critical spacing was reduced and rebalanced between the nasal and temporal hemifields. Furthermore, the postoperative recovery of stereopsis was associated with the extent of nasotemporal balance of critical spacing. CONCLUSIONS. We find that optical realignment (i.e., strabismus surgery) can normalize the enlarged visual crowding effects, a reliable psychophysical index of cortical organization, in the peripheral visual field of older children and adults with strabismus and rebalance the nasotemporal asymmetry of crowding, promoting the recovery of postoperative stereopsis. Our results indicated a potential of experience-dependent cortical organization after axial alignment even for individuals who are out of the critical period of visual development, illuminating the capacity and limitations of optics on sensory plasticity and emphasizing the importance of ocular correction for clinical practice.</p