This study reports the consequences of knocking out NADPH oxidase 4 (Nox4) upon the development of hypertension and kidney injury in the Dahl salt-sensitive (SS) rat. Zinc finger nuclease injection of single cell SS embryos was used to create an 8 base-pair frame-shift deletion of Nox4 resulting in a loss of the ~68 kD band in Western blot analysis of renal cortical tissue of the SSNox4−/− rats. SSNox4−/− rats exhibited a significant reduction of salt-induced hypertension compared to SS rats after 21 days of 4.0% NaCl diet (134±5 vs 151±3 mmHg in SS) and a significant reduction of albuminuria, tubular casts, and glomerular injury. Optical fluorescence 3D cryoimaging revealed significantly higher redox ratios (NADH/FAD) in the kidneys of SSNox4−/− rats even when fed the 0.4% NaCl diet indicating greater levels of mitochondrial electron transport chain metabolic activity and reduced oxidative stress compared to SS rats. Prior to the development of hypertension, RNA expression levels of NADPH oxidase subunits Nox2, p67phox, and p22phox were found to be significantly lower (p<0.05) in SSNox4−/− compared to SS rats in the renal cortex. Thus the mutation of Nox4 appears to modify transcription of a number of genes in ways that contribute to the protective effects observed in the SSNox4−/− rats. We conclude that the reduced renal injury and attenuated blood pressure response to high salt in the SSNox4−/− rat could be the result of multiple pathways including gene transcription, mitochondrial energetics, oxidative stress, and protein matrix production impacted by the knock out of Nox4.

Most of the physiological processes are controlled by the small RNAs in several organisms including plants. A huge database exists on one type of small RNA, i.e., microRNAs (miRs) identified from diverse species. However, the processes of data-mining of miRs in most of the species are still incomplete. Rice feeds the hungry trillions and hence understanding its developmental processes as well as its stress biology, which might be largely controlled by the small RNA pathways, is certainly a worthwhile task. Here, we report the cloning and identification of approximately 40 new putative miRs from local basmati rice variety in accordance to the annotation suggested by Meyers et al. (Plant Cell 20:3186-3190, 2008). About 23 sequences were derived from rice exposed to salt stress while 18 were derived from rice infected with tungro virus. A few of these putative miRs were common to both. Our data showed that at least two of these miRs were up-regulated in response to both abiotic and biotic stresses. The miR target predictions indicate that most of the putative miRs target specific metabolic processes. The up-regulation of similar miRs in response to two entirely different types of stresses suggests a converging functional role of miRs in managing various stresses. Our findings suggest that more rice miRs need to be identified and a thorough understanding of the function of such miRs will help unravel the mysteries of rice stress biology.

In addition to their encapsidation function, viral coat proteins (CP) contribute to viral life cycle in many different ways. The CPs of the geminiviruses are responsible for intra- as well as inter-plant virus transmission and might determine the yield of viral DNA inside the infected tissues by either packaging the viral DNA or interfering with the viral replicative machinery. Since the cognate Rep largely controls the rolling circle replication of geminiviral DNA, the interaction between Rep and CP might be worthwhile to examine for elucidation of CP-mediated control of the viral DNA copy number. Here a reasonably strong interaction between Rep and CP of the geminivirus Mung bean yellow mosaic India virus is reported. The domain of interaction has been mapped to a central region of Rep. The replication initiation activity of Rep, i.e., its nicking and closing function, is down regulated by CP. This report highlights how CP could be important in controlling geminiviral DNA replication.

A 1.37 Mbp region of chromosome 13 previously identified by exclusion mapping was consistently associated with a reduction of salt-induced hypertension in the Dahl salt-sensitive (SS) rat. This region contained five genes that were introgressed from the salt-insensitive Brown Norway (BN) rat. The goal of the present study was to further narrow that region to identify the gene(s) most likely to protect from salt-induced hypertension. The studies yielded a subcongenic SS rat strain containing a 0.71 Mbp insert from BN (26-P strain) in which salt-induced hypertension was reduced by 24 mmHg. The region contained two protein-coding genes (Astn1 and Pappa2) and a microRNA (miR-488). Pappa2 mRNA in the renal cortex of the protected 26-P was 6- to 10-fold greater than in SS fed a 0.4% NaCl diet but was reduced to levels observed in SS when fed 8.0% NaCl diet for 7 days. Compared with brain nuclei (NTS, RVLM, CVLM) and the adrenal gland, Pappa2 in the renal cortex was the only gene found to be differentially expressed between SS and 26-P and that responded to changes of salt diet. Immunohistochemistry studies found Pappa2 localized in the cytosol of the epithelial cells of the cortical thick ascending limbs. In more distal segments of the renal tubules, it was observed within tubular lumens and most notably bound to the apical membranes of the intercalated cells of collecting ducts. We conclude that we have identified a variant form of Pappa2 that can protect against salt-induced hypertension in the Dahl S rat.

Introduction The present study explored the mechanism of mTORC2 activation in Sprague Dawley (SD) rats and the protective effect of mTORC2 inhibition in salt‐induced hypertension and kidney injury in Dahl salt‐sensitive (SS) rats. Although there are evidences that the mTORC2 pathway contributes to renal podocyte homeostasis and tubular epithelial Na+ and K+ transport, this pathway has remained unexplored in hypertension. Since excess production of H2O2 in the kidney is the hallmark of salt‐induced hypertension in the SS rat, we hypothesized that H2O2 may stimulate mTORC2 and contributes to this salt‐sensitive form of hypertension. Methods H2O2 (347 nmol/Kg/min) was chronically infused for 3 days into renal medullary interstitium of unilaterally nephrectomized (SD) rats to determine the in vivo consequence of H2O2 upon mTORC2 activity. To test the protective effect of PP242 (ATP competitive inhibitor of both mTORC1 and mTORC2), SS rats were divided in to four groups. Groups 1 and 2: vehicle (group 1) or PP242 (group 2) was administrated daily (i.p., 15 mg/Kg/day) for 4 days to SS rats fed a 0.4% NaCl diet (control), then switched to a 4.0% NaCl diet for 21 days. Groups 3 and 4: rats were fed 4.0 % NaCl for 7 days before being treated with vehicle (group 3) or PP242 (group 4) for next 14 days while maintained on the 4.0 % NaCl diet. Kidneys were harvested to measure the protein levels of pAKT S473 and AKT by Western blots. mTORC2 activity was determined by assessing the ratio pAKTS473 and AKT. Microalbuminuria was quantified and kidney sections were immunostained with antibody against anti‐CD3 to determine the renal T lymphocytes infiltration. Results A significant increase of mTORC2 (pAKT S473/AKT) activity was observed in the renal cortex of SD rats infused with H2O2 for 3 days compared to saline infused rats. PP242 treatment significantly reduced H2O2 stimulated mTORC2 activity in nephron segments isolated from SS rat kidneys in vitro. Daily adminsiration of PP242 significantly reduced salt‐induced blood pressure in SS rats which averaged 119 ± 2 mmHg in group 2 rats (n=7) compared to 168 ± 3 mmHg in group 1 rats (n=7). Importantly, PP242 reversed the hypertension from 143 ± 3 mmHg to the base line 126 ± 5 mmHg in 2 days and maintained it at similar levels over the next 12 days in the group 4 rats (n=7) compared with group 3 rats (n=6). Albuminuria was greatly reduced with urine albumin excretion (mg/day) averaging 32.8 ± 3 in group 2 rats compared to 256 ± 37 in group 1 rats. PP242 treatment notably reduced infiltration of T lymphocytes in the kidneys of SS rats fed a 4.0% NaCl diet. CD3+ cells/mm2 averaging 36.0 ± 11.0 compared to 157.0 ± 40.0 in the cortex and 24.0 ± 9.0 compared to 218.0 ± 24.0 in the outer medulla in group 2 versus group 1 rats. Conclusion These data show that mTORC2 is required for the initiation of salt‐induced hypertension and therapeutic suppression of this pathway prevents and reverses the salt‐induced hypertension and and kidney injury in SS rats. This abstract is from the Experimenta...

The goal of the present study was to explore the protective effects of mTORC1 inhibition by rapamycin on salt-induced hypertension and kidney injury in Dahl salt-sensitive (SS) rats. We have previously demonstrated that H2O2 is elevated in the kidneys of SS rats. The present study showed a significant upregulation of renal mTORC1 activity in the SS rats fed a 4.0% NaCl for 3 days. Additionally, renal interstitial infusion of H2O2 into salt-resistant Sprague Dawley (SD) rats for 3 days was also found to stimulate mTORC1 activity independent of a rise of arterial pressure (BP). Together, these data indicate that the salt-induced increases of renal H2O2 in SS rats activated the mTORC1 pathway. Daily administration of rapamycin (i.p., 1.5 mg/Kg/day) for 21 days reduced salt-induced hypertension from 176.0 ± 9.0 to 153.0 ± 12.0 mmHg in SS rats but had no effect on BP salt-sensitivity in SD treated rats. Compared to vehicle, rapamycin reduced albumin excretion rate in SS rats from 190.0 ± 35.0 to 37.0 ± 5.0 mg/day and reduced the renal infiltration of T lymphocytes (CD3+) and macrophages (ED1+) in the cortex and medulla. Renal hypertrophy and cell proliferation was also reduced in rapamycin treated SS rats. We conclude that enhancement of intrarenal H2O2 with a 4.0% NaCl diet stimulates the mTORC1 pathway which is necessary for the full development of the salt-induced hypertension and kidney injury in the SS rat.

Development of abiotic stress tolerant rice cultivars is necessary for sustainable rice production under the scenario of global climate change, dwindling fresh water resources and increase in salt affected areas. Several genes from rice have been functionally validated by using EMS mutants and transgenics. Often, many of these desirable alleles are not available indica rice which is mainly cultivated, and where available, introgression of these alleles into elite cultivars is a time and labour intensive process, in addition to the potential introgression of non-desirable genes due to linkage. CRISPR-Cas technology helps development of elite cultivars with desirable alleles by precision gene editing. Hence, this study was carried out to create mutant alleles of drought and salt tolerance (DST) gene by using CRISPR-Cas9 gene editing in indica rice cv. MTU1010. We used two different gRNAs to target regions of DST protein that might be involved in protein-protein interaction and successfully generated different mutant alleles of DST gene. We selected homozygous dst mutant with 366 bp deletion between the two gRNAs for phenotypic analysis. This 366 bp deletion led to the deletion of amino acid residues from 184 to 305 in frame, and hence the mutant was named as dst D184-305 . The dst D184-305 mutation induced by CRISPR-Cas9 method in DST gene in indica rice cv. MTU1010 phenocopied EMS-induced dst (N69D) mutation reported earlier in japonica cultivar. The dst D184-305 mutant produced leaves with broader width and reduced stomatal density, and thus enhanced leaf water retention under dehydration stress. Our study showed that the reduction in stomatal density in loss of function mutants of dst is, at least, in part due to downregulation of stomatal developmental genes SPCH1, MUTE and ICE1. The Cas9-free dst D184-305 mutant exhibited moderate level tolerance to osmotic stress and high level of salt stress in seedling stage. Thus, dst mutant alleles generated in this study will be useful for improving drought and salt tolerance and grain yield in indica rice cultivars.

The present study was aimed at characterizing cytoplasmic male sterility (CMS) and identifying the fertility restorer gene for CMS (Diplotaxis catholica) Brassica juncea derived through sexual hybridization. The fertility restorer gene was identified by crossing the CMS line with progeny plants derived from somatic hybrids of B. juncea and D. cathoilca. The CMS line is comparable to the nuclear donor B. juncea in all respects except for flower and silique characteristics. In CMS plants, the flowers have smaller nectaries, and anthers are converted into petals or tubular structures. Gynoecium exhibits a crooked style and trilocular ovary. Seed fertility was reduced in the CMS line. Genetic segregation data indicated that a single, dominant, nuclear gene governs fertility restoration. Restored plants showed a high female fertility and lacked gynoecium abnormalities. In fertility-restored plants, petal development was found to be variable; some flowers had the normal number of four petals, while others had zero to three petals. Interestingly, the trilocular character of the ovary was found to co-segregate with CMS and became bilocular upon male-fertility restoration. Thus, this trait appears to be affected by the interaction of nuclear and mitochondrial (mt) genomes. Restriction fragment length polymorphism analysis indicated that mt-genome of D. catholica is highly divergent from that of B. juncea. However, in Northern analysis, out of eight mt genes studied, an altered transcript pattern was recorded for only atpA. In fertility-restored plants, the atpA transcript became shorter, thereby showing its association with CMS.