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Home > Study of Salt Stress-Induced Alterations in Signal Transduction Pathways in Oryza Sativa by Expression Profiling

Study of Salt Stress-Induced Alterations in Signal Transduction Pathways in Oryza Sativa by Expression Profiling

Thesis Info

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Author

Ijaz, Bushra

Program

PhD

Institute

COMSATS University Islamabad

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2019

Thesis Completion Status

Completed

Subject

Bio sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/11826/1/Bushra%20Ijaz%20bioscience%202019%20comsats%20isb%20prr.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727391081

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Salinity is one of the most important abiotic stresses that affect crop production globally as well as in Pakistan. Rice is regarded as an important cereal crop prone to salinity which drastically reduces its yield. This study was conducted to underpin the transcriptional changes in regulating genes engaged at different nodes of salt stressinduced signaling pathways in rice. Five indica rice cultivars of Pakistan viz. KSK-133, KS-282, Super Basmati, Shaheen Basmati and DilRosh were hydroponically given salt stress using 75, 100 and 150 mM NaCl as final concentrations. The optimal salt stress dose was identified as 100 mM at which Super Basmati was found sensitive to salt treatment while KS-282 was marked as salt tolerant amongst the five cultivars tested. The amounts of Na+ and K+ ions were compared for the two contrasting cultivars. High Na+ amounts were measured in the roots and shoots of the salt-sensitive Super Basmati plants three days post treatment as compared to salt tolerant KS-282 plants. The root architectural analysis showed a significant decrease in the root growth and lateral root density in Super Basmati 7 days post treatment along with reduced root surface area when compared to KS-282. We further investigated the change in the transcript concentration of stress-related genes (OsOSCA1.1, OsRbohA, OsDREB2A) and genes specifically known for Na+ homeostasis (OsNHX1, OsSOS1and OsHKT1.5) by qPCR. Interestingly, the relative transcript concentration of OsOSCA1.1, OsRbohA, OsDREB2A was significantly lower at 30 minutes post salt stress in Super Basmati while in KS-282, the expression level for these genes remained many folds high. Considering transcript accumulation for OsNHX1, OsSOS1 and OsHKT1.5, no significant difference was noticed in Super Basmati at 1 and 6 hours post treatment while in the relatively salt tolerant KS-282 plants, a remarkable increase in the transcript accumulation was observed 6 hours post treatment suggesting an important role of these genes. Similarly, a strong relationship between the expression of OsTPKa and OsHAK5 and plant K+ levels was noticed in KS-282, while OsKAT1 showed no change in the expression. The salt stress response in both Super Basmati and KS-282 was further investigated through cell cultures after working out the optimal media and hormone combination for callus induction and whole-plant regeneration. In the stabilized cell xii cultures independently grown on 100 mM NaCl, significantly high intracellular hydrogen peroxide (H2O2) and nitric oxide (NO) were found in Super Basmati cultures compared to KS-282. These data suggest a better ROS scavenging in KS-282 to cope with oxidative stress and cell damage caused by redox imbalance as a consequence of salt stress. To evaluate the role of NO in inducing cell death after salt stress, cell death percentage (CDP) was measured after NO scavenging through 2-4-carboxyphenyl4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO). CDP was reduced significantly in cell cultures of both salt tolerant and sensitive cultivars emphasizing role of NO in programmed cell death. The transcript of OsRbohA, which encodes a plasma membrane NADPH oxidase, and genes of OSCA family members (OsOSCA1.1, OsOSCA1.2 and OsOSCA3.1) was quantified and found to be highly upregulated in the cell cultures of KS-282. The activity of ascorbate peroxidase and catalase was higher in KS-282 cells while the activity of superoxide dismutase was significantly higher in the Super Basmati cell cultures. Salt stress and ROS-responsive genes encoding transcription factors, OsSERF1 and OsDREB2A, were found to be upregulated relatively early in the KS-282 cells cultures, while not in Super Basmati. Similarly, the transcript of genes involved in maintaining a high [K+]/[Na+] ratio raised considerably higher and earlier in the cell cultures of the tolerant cultivar. These data suggest that the prompt upregulation of stress responsive genes and associated transcription factors transduces the stress signal by maintaining K+ and Na+ ion homeostasis and thus playing a dynamic role in salinity tolerance in rice plants and corresponding cell cultures. We also reported differential expression of OSCA genes in response to salt stress in rice. Based on our data we postulate a new potential model presenting crosstalk between important second messengers i.e. ROS, RNS and Ca2+ which may elucidate the mechanisms underlying salt stress signal transduction in rice.
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ڈیجیٹل بچے

 ڈیجیٹل بچے

محمد علی صدیقی

"انٹرنیٹ اور موبائیل نے نوجوان نسل کو کہاں پہنچا دیا ہے سمجھ میں نہیں آتا۔ آنے والا کل نہ جانے کیسا ہو۔!!۔" مینیجنگ کمیٹی کے صدر نے فکرمند لہجے میں کہا۔

"اتنی مایوسی ٹھیک نہی" میں نے کہا۔

میں کچھ اور بھی کہنے والا تھا کہ ایک ٹیچر درجہ چہارم کی ایک بچی کو لے کر آفس میں داخل ہوئیں اور بولیں

"سر یہ آپ سے کچھ کہنا چاہتی ہے۔"

"ہاں۔ کہو" میں نے ان کی طرف متوجہ ہوتے ہوئے کہا۔

"سر۔۔۔ کلاس میں ایک لڑکا مجھے بھابھی بلاتا ہے۔"

وہ اپنی مسکراہٹ چھپانے کی ناکام کوشش کر رہی تھی۔ مجھے کچھ عجیب سا لگا۔ میں نے اس بچے کو بلا کر وارننگ دی اور ٹیچر سے کہا

"آپ لوگ یہ شکایتیں خود ہی سن لیا کریں۔ آفس میں نہ لایا کریں۔"

"ہم تو سنتے ہی رہتے ہیں سر۔ میں نے سوچا کہ آج آپ بھی سن لیں" ٹیچر نے تھکے ہوئے لہجے میں کہا، " کل کے۔جی کا ایک بچہ اپنے ساتھ بیٹھی بچی سے پوچھ رہا تھا کہ کیا وہ اس سے پیار کرتی ہے۔ بچی کی شکایت پر میں نے ان دونوں کو الگ الگ بٹھا دیا لیکن کچھ ہی دیر بعد دونوں پھر ایک ساتھ بیٹھے باتیں کرتے نظر آئے۔"

میں نے ٹیچر کو جانے کا اشارہ کیا اور صدر کی طرف دیکھا۔ ان کے چہرے پر ایک معنی خیز مسکراہٹ کھیل رہی تھی۔

 

Right to Life As a Human Right: A Comparative Study of Shari’ah and Law

AbstractABSTRACT: Right to Life is considered as one of the primordial Human Rights. The importance of right to life can be judged simply on this basis that there are diversified views ofthe leaders of the world regarding almost every issue about human Rights concern. However, they agree in principle that the individuals (lives) irrespective of their race, color, language and nationality, should be saved andprotected and they should be honored and respected. Even a cursory glance at the contents of the Islamic ideology indicates that the Qura'n and the Sunna'h have dealt in depth with nearly every aspect of human rights and in particular the right to life. The present study investigates different aspects and dimensions of ‘Right to life’ in the light of Islam, along with its comparison with law and western approaches to it.

Evaluation of Different Cropping Patterns under Command Area of Small Dams in Pothwar: A Case Study of Pira Fatehal Dam

Small dams have been constructed in Pothwar region with huge investment for supplementary irrigation. However, farmers in command area (the area around the dam where the irrigation water reaches or that can be irrigated from a dam and is fit for cultivation) of small dams have not benefited from this precious water and are still doing traditional agriculture such as summer fallowing etc. Non-existence of suitable cropping pattern may be one reason. Therefore, different cropping patterns (i) fallow-wheat (Fallow-Triticum aestivum) (CP-1), (ii) mash bean - wheat (Vigna mungo-Triticum aestivum) (CP-2), (iii) sorghum - wheat (Sorghum bicolor-Triticum aestivum) (CP-3), (iv) maize (grain) - wheat (Zea mays-Triticum aestivum) (CP-4), (v) maize (grain) - chick pea (Zea mays-Cicer arietinum) (CP-5) and (vi) mung bean - canola (Vigna radiata -Brassica napus) (CP-6) were evaluated for agro economic efficiencies under command area of Pira fatehal dam as well as for adjacent uncommand or rain-fed area, on sandy loam soil for two years. Highest grain yield of wheat (winter crops) was obtained from mash beanwheat (Vigna mungo-Triticum aestivum) (CP-2) as compared to those from maize-wheat (Zea mays-Triticum aestivum) (CP-4), fallow-wheat (fallow-Triticum aestivum) (CP-1) and sorghum - wheat (Sorghum bicolour-Triticum aestivum) (CP-3) cropping patterns, respectively, under both the environments. Chick pea grain yield remained lowest under both the environments. Regarding summer crops, sorghum fodder (Sorghum bicolour), maize grain (Zea mays) and mash bean (Vigna mungo) performed excellent in terms of economic and grain yield. On the other hand, mung bean (Vigna radiata) reflected poor response for grain yield under both the environment. Benefit cost ratio of 7.17% and 5.35% for mash bean-wheat (Vigna mungo-Triticum aestivum) (CP-2) was highest under both the environments, while lowest benefit cost ratio (5.12 %) was exhibited from maizechick pea (Zea mays-Cicer arietinum) (CP-5) under irrigated and (1.37%) 19 from mung bean-canola (Vigna radiata -Brassica napus) (CP-6) under rain-fed environment, respectively. Highest net returns were obtained from maize-wheat (Zea mays-Triticum aestivum) (CP-4) cropping pattern under irrigated while from mash bean-wheat (Vigna mungo-Triticum aestivum) (CP-2) cropping pattern under rainfed environment. Mung bean-canola (Vigna radiata -Brassica napus) (CP-6) proved the lowest in terms of net returns from both the environments. Highest marginal rate of return was exhibited by mash bean-wheat (Vigna mungo-Triticum aestivum) (CP- 2) when compared with fallowwheat (Fallow-Triticum aestivum) (CP-1), while maize-wheat (Zea mays-Triticum aestivum) (CP-4) and sorghum - wheat (Sorghum bicolour-Triticum aestivum) (CP-3) ranked 2nd and 3rd on marginal rate of return basis in the same comparison, under irrigated environment. On the other hand, mash bean-wheat (Vigna mungo-Triticum aestivum) (CP2) ranked 1st and mung beancanola (Vigna radiata -Brassica napus) (CP-6) ranked 2nd when compared with fallow-wheat (Fallow-Triticum aestivum) (CP-1) for marginal rate of return in rainfed environment. Water use efficiency of wheat, following mash bean under both the environments exhibited higher values when compared with those from sorghumwheat, fallow-wheat and maize-wheat cropping patterns. Mung bean showed poor response among all the cropping patterns for exhibiting water use efficiency under both environments. Cropping intensities (of 200 %) from all the cropping patterns except fallow-wheat (100%) were recorded from both the environments. During the course of study, 2nd year summer and winter crops received higher rainfalls than that of first year, which affected the economic yields of crops under rain-fed environment, where as performance of all crops remained better under irrigated environment during both the seasons and years, as below average rainfalls were compensated by supplementary irrigations. Hence, this study concludes that farmers having supplemental irrigation water resources should adopt maize (grain)– 20 wheat (Zea mays-Triticum aestivum) (CP-4) cropping pattern, based on economical return as well as efficient utilization of available supplemental water, whereas, based on improved nutrient utilization and monetary outputs, mash bean-wheat (Vigna mungo-Triticum aestivum) (CP-2) cropping pattern should be followed under rainfed areas for better resource management. Also summer fallowing practice is not economical for farmers under both irrigated and rain-fed environments.