scholarly journals Mapping and Identification of Genetic Loci Affecting Earliness of Bolting and Flowering in Lettuce

Author(s):  
Leah Rosental ◽  
David W. Still ◽  
Youngsook You ◽  
Ryan J. Hayes ◽  
Ivan Simko

Abstract Bolting, defined as stem elongation, marks the plant life cycle transition from vegetative to reproductive stage. Lettuce is grown for its leaf rosettes, and premature bolting may reduce crop quality resulting in economic losses. The transition to reproductive stage is a complex process that involves many genetic and environmental factors. In this study the effects of photoperiod and ambient temperature on bolting and flowering regulation was studied by utilizing a lettuce mapping population to identify quantitative trait loci (QTL) and by gene expression analyses of genotypes with contrasting phenotypes. A recombinant inbred line (RIL) population, derived from a cross between PI251246 (early bolting) and cv. Salinas (late bolting), was grown in four combinations of short (8 hours) and long (16 hours) days and low (20°C) and high (35°C) temperature. QTL models revealed both genetic (G) and environmental (E) effects, and GxE interactions. A major QTL for bolting and flowering time was found on chromosome 7 (qFLT7.2) and two candidate genes were identified by fine mapping, homology and gene expression studies. In short days and high temperature conditions qFLT7.2 had no effect on plant development, while several small-effect loci on chromosomes 2, 3, 6, 8 and 9 were associated with bolting and flowering. Of these, the QTL on chromosome 2, qBFr2.1, co-located with the Flowering Locus T (LsFT) gene. Polymorphisms between parent genotypes in the promotor region may explain identified gene expression differences, and were used to design a genetic marker which may be used to identify the late bolting trait.

2020 ◽  
Vol 139 ◽  
pp. 153-160
Author(s):  
S Peeralil ◽  
TC Joseph ◽  
V Murugadas ◽  
PG Akhilnath ◽  
VN Sreejith ◽  
...  

Luminescent Vibrio harveyi is common in sea and estuarine waters. It produces several virulence factors and negatively affects larval penaeid shrimp in hatcheries, resulting in severe economic losses to shrimp aquaculture. Although V. harveyi is an important pathogen of shrimp, its pathogenicity mechanisms have yet to be completely elucidated. In the present study, isolates of V. harveyi were isolated and characterized from diseased Penaeus monodon postlarvae from hatcheries in Kerala, India, from September to December 2016. All 23 tested isolates were positive for lipase, phospholipase, caseinase, gelatinase and chitinase activity, and 3 of the isolates (MFB32, MFB71 and MFB68) showed potential for significant biofilm formation. Based on the presence of virulence genes, the isolates of V. harveyi were grouped into 6 genotypes, predominated by vhpA+ flaB+ ser+ vhh1- luxR+ vopD- vcrD+ vscN-. One isolate from each genotype was randomly selected for in vivo virulence experiments, and the LD50 ranged from 1.7 ± 0.5 × 103 to 4.1 ± 0.1 × 105 CFU ml-1. The expression of genes during the infection in postlarvae was high in 2 of the isolates (MFB12 and MFB32), consistent with the result of the challenge test. However, in MFB19, even though all genes tested were present, their expression level was very low and likely contributed to its lack of virulence. Because of the significant variation in gene expression, the presence of virulence genes alone cannot be used as a marker for pathogenicity of V. harveyi.


2018 ◽  
Vol 7 (2) ◽  
Author(s):  
Made Pharmawati ◽  
Ni Nyoman Wirasiti ◽  
Luh Putu Wrasiati

Abstrak Cekaman kekeringan merupakan faktor pembatas penting bagi pertumbuhan dan produktivitas tanaman termasuk padi.      Penelitian ini bertujuan menganalisis respon padi IR64 terhadap cekaman kekeringan dengan pemberian polietilen glikol (PEG) pada fase reproduktif.  Penelitian juga bertujuan menganalisis ekspresi gen aquaporin akibat cekaman kekeringan.  Bibit padi ditanam dalam pot dan perlakuan PEG dengan konsentrasi 108g/L (-0.25MPa) dan 178g/L (-0.52 MPa) diberikan saat munculnya panikula. Perlakuan diberikan selama 2 minggu, kemudian tanaman disiram kembali.  Ekspresi gen diamati pada akhir perlakuan dengan semi kuantitatif real time PCR.  Ekstraksi RNA menggunakan RNeasy plant mini kit, sedangkan sintesis cDNA menggunakan Transcriptor First Strand cDNA Kit.  Hasil penelitian menunjukkan bahwa jumlah malai dan berat total malai berkurang akibat cekaman kekeringan.  Persentase gabah kosong mencapai 84,6% pada perlakuan PEG-0,52 MPa, sedangkan pada perlakuan PEG -0,25 MPa persentase gabah kosong sebesar 67,8%.  Pada kontrol persentase gabah kosong adalah 10,3%.  Ekspresi gen OsPIP2;7 sedikit menurun pada perlakuan PEG -0,52 MPa.Kata kunci: ekspresi gen, IR64, kekeringan, padi, PEG  Abstract Drought stress is one of the limiting factors of plant growth and productivity including rice.  The aim of this study was to analyze responses of IR64 rice to polyethylene glycol (PEG)-induced-drought stress at the reproductive stage.  This study also aimed to analyze the expression of aquaporin under drought stress.  Rice seedlings were grown in pot system and PEG treatment at concentration of -0.25MPa (108g/L) and -0.52 MPa (178g/L) were given when the panicles arose.  Treatments were conducted for 2 weeks, after that the plants were rewatered.  Gene expression was evaluated at the end of PEG treatment using semi quantitative real time PCR. RNA was extracted using RNeasy plant mini kit, while cDNA synthesis was done using Transcriptor First Strand cDNA Kit.  The results showed that the number and weight of rice ear were less in plant treated with PEG than in control.  The percentage of empty rice grain reached 84.6% at PEG -0.52 MPa, while at PEG -0.25 MPa the percentage of empty grain was 67.8%.  In control plant, the percentage of empty grain was 10.3%.  Drought stress did not alter the expression of OsPIP2;7.  Keywords: drought, gene expression, IR64, PEG, rice


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kim Hoa Ho ◽  
Annarita Patrizi

AbstractChoroid plexus (ChP), a vascularized secretory epithelium located in all brain ventricles, plays critical roles in development, homeostasis and brain repair. Reverse transcription quantitative real-time PCR (RT-qPCR) is a popular and useful technique for measuring gene expression changes and also widely used in ChP studies. However, the reliability of RT-qPCR data is strongly dependent on the choice of reference genes, which are supposed to be stable across all samples. In this study, we validated the expression of 12 well established housekeeping genes in ChP in 2 independent experimental paradigms by using popular stability testing algorithms: BestKeeper, DeltaCq, geNorm and NormFinder. Rer1 and Rpl13a were identified as the most stable genes throughout mouse ChP development, while Hprt1 and Rpl27 were the most stable genes across conditions in a mouse sensory deprivation experiment. In addition, Rpl13a, Rpl27 and Tbp were mutually among the top five most stable genes in both experiments. Normalisation of Ttr and Otx2 expression levels using different housekeeping gene combinations demonstrated the profound effect of reference gene choice on target gene expression. Our study emphasized the importance of validating and selecting stable housekeeping genes under specific experimental conditions.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lalit Sharma ◽  
Aditi Sharma ◽  
Ashutosh Kumar Dash ◽  
Gopal Singh Bisht ◽  
Girdhari Lal Gupta

Abstract Background Alcohol abuse is a major problem worldwide and it affects people’s health and economy. There is a relapse in alcohol intake due to alcohol withdrawal. Alcohol withdrawal anxiety-like behavior is a symptom that appears 6–24 h after the last alcohol ingestion. Methods The present study was designed to explore the protective effect of a standardized polyherbal preparation POL-6 in ethanol withdrawal anxiety in Wistar rats. POL-6 was prepared by mixing the dried extracts of six plants Bacopa monnieri, Hypericum perforatum, Centella asiatica, Withania somnifera, Camellia sinesis, and Ocimum sanctum in the proportion 2:1:2:2:1:2 respectively. POL-6 was subjected to phytochemical profiling through LC-MS, HPLC, and HPTLC. The effect of POL-6 on alcohol withdrawal anxiety was tested using a two-bottle choice drinking paradigm model giving animals’ free choice between alcohol and water for 15 days. Alcohol was withdrawn on the 16th day and POL-6 (20, 50, and 100 mg/kg, oral), diazepam (2 mg/kg) treatment was given on the withdrawal days. Behavioral parameters were tested using EPM and LDT. On the 18th day blood was collected from the retro-orbital sinus of the rats and alcohol markers ALT, AST, ALP, and GGT were studied. At end of the study, animals were sacrificed and the brain was isolated for exploring the influences of POL-6 on the mRNA expression of GABAA receptor subunits in the amygdala and hippocampus. Results Phytochemical profiling showed that POL-6 contains major phytoconstituents like withaferin A, quercetin, catechin, rutin, caeffic acid, and β-sitosterol. In-vivo studies showed that POL-6 possesses an antianxiety effect in alcohol withdrawal. Gene expression studies on the isolated brain tissues showed that POL-6 normalizes the GABAergic transmission in the amygdala and hippocampus of the rats. Conclusion The study concludes that POL-6 may have therapeutic potential for treating ethanol-type dependence.


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