Imron RIYADI
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Kloning dan karakterisasi daerah promoter gen penyandi ADP glucose pyrophosphorylase dari Metroxylon sagu rendemen pati-tinggi dan -rendah [Cloning and characterization of promoter region of ADP glucose pyrophosphorylase-encoding gene from Metroxylon sagu with high- and low-starch content] Asmini BUDIANI; Riza Arief PUTRANTO; Hayati MINARSIH; Imron RIYADI; . SUMARYONO; Barahima ABBAS
Menara Perkebunan Vol. 84 No. 1 (2016): 84 (1), 2016
Publisher : INDONESIAN OIL PALM RESEARCH INSTITUTE

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22302/iribb.jur.mp.v84i1.200

Abstract

ADP-glucose pyrophosphorylase (AGPase) is one of the key enzymes in the starch biosynthesis. In many plants, the activity of this enzyme was reported to affect the yield and composition of the produced starch. This research is a part of an effort to develop molecular markers for early selection of high starch-yielding of sago palm. The purpose of the research was to isolate promoters of AGP gene and to analyze the differences in their DNA sequences between sago palm with high starch content (MsHS) and low starch content (MsLS). DNA was isolated and purified from the leaves of the two sago palm. The promoter region of AGP was amplified by Genome Walking technique. The specific primers were designed by Primer3 program based on the information of DNA sequence of AGP genes of sago palm from previous studies. Selected DNA fragments resulted from Genome Walking were isolated from the gel, cloned into E. coli, and analyzed its DNA sequence. DNA sequence analysis showed that one DNA fragment from MsHS  (± 1500 bp) and one DNA fragment from MsLS (> 2000 bp) were confirmed as a 5’ upstream of the AGP gene.  Further in silico analysis using MEME program identified various DNA motifs of cis-acting elements, which confirmed that those DNA fragment were promoter region of the gene. Preliminary analysis showed the differences in DNA sequences and motives of cis-acting elements in the promoter region of the two samples which might influence or indirectly associated with the character of the starch yield in sago palm.
Pengaruh jumlah subkultur dan media sub-optimal terhadap pertumbuhan dan kemampuan regenerasi kalus tebu (Saccharum officinarum L.) (Effect of repeated subculture and suboptimum media on the growth of sugarcane calli (Saccharum officinarum L.)) Hayati MINARSIH; . Suharyo; Imron RIYADI; Diah RATNADEWI
Menara Perkebunan Vol. 84 No. 1 (2016): 84 (1), 2016
Publisher : INDONESIAN OIL PALM RESEARCH INSTITUTE

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22302/iribb.jur.mp.v84i1.219

Abstract

Sugarcane (Saccharum officinarum L.) is an important crop for sugar production. One attempt to increase sugarcane productivity is through micropropagation and quality improvement of sugarcane seedlings in vitro. This research aimed to study the effect of repeated subcultures on callus capacity for regeneration and plant survival in acclimatization phase, as well as the influence of suboptimum media on the recovery capability of sugarcane callus to proliferate in vitro. Fourth subcultured sugarcane callus derived from young leaves were used as material in this research. Basic medium of Murashige and Skoog (MS) added with 3 mg/L 2,4-D, 10% coconut water, and 3% sucrose was used for callus initiation. For callus regeneration, the MS medium was supplemented with 2 mg/L BAP, 0.2 mg/L IAA, 10% coconut water, and 3% sucrose. Study on the effect of subculture numbers consisted of three stages, i.e. initiation, regeneration, and acclimatization, while the study on resting phase or the use of sub-optimal media included six treatment media and two pathways. Results showed that the fifth subcultures produced embryoid callus (91%), the highest non mucilaginous callus (97%), and the highest abnormality rate (6%). Results from the suboptimum media treatment, showed that B pathway (4 week resting phase) was better than the A pathway (8 week resting phase), based on fresh weight and callus abnormality percentage. A and B pathways indicated that the growth of callus can be recovered when it was grown back to the normal media and 1.5D-MS treatment of the resting phase showed the best growth and appearance. 
Pengaruh kitosan, mikroba antagonis, dan bakteri endofit dalam menekan perkembangan penyakit bercak daun pada bibit kelapa kopyor (Effect of chitosan, antagonist and endophytic bacteria in suppressing the development of leaf spot disease in kopyor coconut seedlings) Deden Dewantara ERIS; Sri WAHYUNI; Imron RIYADI; Happy WIDIASTUTI; . SISWANTO
Menara Perkebunan Vol. 87 No. 1 (2019): 87 (1), 2019
Publisher : INDONESIAN OIL PALM RESEARCH INSTITUTE

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22302/iribb.jur.mp.v87i1.324

Abstract

Currently, tissue culture is one of the best techniques in propagating of kopyor coconut. The important stage in plant propagation through tissue culture is acclimatization. Upon entering the acclimatization stage, the problem that couldarise in kopyor coconut seedlings is leaf spot disease caused by the fungus Colletotrichumsp., Curvularia sp. and Pestalotiopsissp. Environmentally friendly leaf spot disease control techniques can be done through the use of chitosan, antagonists microbes and endophytic bacteria. This study aimed to examine the use of chitosan, microbial antagonists, endophytic bacteria and their combinations to control leaf spot kopyor coconut disease in four different disease severity categories, namely severe/heavy, moderate, mild, and healthy.Disease development was observed every three weeks, while  the rate of disease infection, area under the disease development curve (AUDPC) and disease progression/delta were observed 15 weeks after treatment. The result showed that in heavy severity category, endophytic bacteria treatment was more effective to inhibit leaf spot disease showed by AUDPC value of 131.95 units that significantly different compared to others. In the moderate category, combination treatment was more effective to suppress leaf spot disease, showed by the lowest infection rate by 0.03 unit per week, and percentage disease value   progression changes was 12.10%, with no significantly different AUDPC value to  the other treatments. In mild and healthy severity category, there were no significanly different  between the rate of infection and AUDPC in all treatments. While the percentage of change progression disease was significantly different between endophytic treatment and control. [Keywords: coconut kopyor seedling, leaf spot disease, antagonist microbes, endophyticbacteria, chitosan]Abstrak Saat ini, teknik kultur jaringan merupakan salah satu teknik terbaik untuk memproduksi bibit kelapa kopyor. Tahap penting dalam perbanyakan tanaman melalui kultur jaringan adalah aklimatisasi. Pada saat memasuki tahap aklimatisasi, masalah yang dapat muncul pada bibit kelapa kopyor adalah serangan penyakit bercak daun yang disebabkan oleh cendawan Colletotrichumsp., Curvulariasp. dan Pestalotiopsis sp.Teknik pengendalian penyakit bercak daun yang ramah lingkungan dapat melalui pemanfaatan kitosan, mikroba antagonis dan bakteri endofit. Penelitian ini bertujuan untuk menguji pengaruh kitosan, mikroba antagonis, bakteri endofit dan kombinasinya untuk mengendalikan penyakit bercak daun bibit kelapa kopyor pada empat kategori keparahan penyakit yang berbeda yaitu berat, sedang, ringan, dan sehat. Perkembangan penyakit diamati setiap tiga minggu selama 15 minggu sedangkan  laju infeksi penyakit, luas area dibawah kurva perkembangan penyakit (AUDPC)dan persentase selisih/delta perkembangan penyakit dihitung pada minggu ke 15.Hasil penelitian menunjukkan bahwa pada bibit kelapa kopyor dengan kategori keparahan berat, perlakuan bakteri endofit lebih efektif menghambat bercak daun dengan menghasilkan nilai AUDPC terkecil yaitu sebesar 131,95 unit dan berbeda nyata dibandingkan dengan perlakuan lainnya sedangkan laju infeksi dan persentase delta perkembangan penyakit tidak berbeda nyata dibandingkan dengan perlakuan lainnya. Pada bibit kopyor kategori keparahan sedang, perlakuan kombinasi lebih efektif menekan bercak daun ditunjukkan dengan laju infeksi terendah sebesar 0,03 unit per minggu yang menghasilkan delta perkembangan penyakit terkecil yakni sebesar 12,1%, dengan nilai AUDPC tidak berbeda nyata dibandingkan dengan perlakuan lainnya. Pada bibit kopyor kategori keparahan ringan dan sehat, tidak terdapat perbedaan yang nyata untuk parameter laju infeksi dan nilai AUDPC pada semua perlakuan. Sedangkan nilai persentase delta perkembangan penyakit pada perlakuan endofit berbeda nyata dibandingkan dengankontrol. [Kata Kunci: bibit kelapa kopyor, penyakit bercak daun, kitosan, mikroba antagonis, bakteri endofit]
Physiological responses and P5CS gene expression of transgenic oil palm plantlet induced by drought stress Turhadi TURHADI; Hayati MINARSIH; Imron RIYADI; . PRIYONO; Asmini BUDIANI
Menara Perkebunan Vol. 88 No. 2 (2020): 88 (2), 2020
Publisher : INDONESIAN OIL PALM RESEARCH INSTITUTE

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22302/iribb.jur.mp.v88i2.386

Abstract

Drought is one of the limiting factors in crop cultivation, such as in oil palm (Elaeis guineensis Jacq.). The transgenic approaches are expected to increase plant tolerance to drought stress and minimize low productivity when drought occurs. Proline is an osmoprotectant compound in plants which its biosynthesis involved the P5CS gene. The objective of this study was to evaluate the tolerance level of P5CS-transgenic oil palm to drought stress induced by polyethylene glycol 6000 (PEG-6000). In this present study, the transgenic and non-transgenic oil palms were treated by  0, 2, and 4% PEG-6000 under in vitro conditions. The experiment was arranged as a factorial completely randomized design with three replications. The drought level score, total chlorophyll content, carotenoids, and proline content, as well as P5CS gene expression in leaf tissues were observed at 7 and 14 days after stress treatments. The result showed that transgenic plantlets had a lower drought level score than those of non-transgenic lines. A concentration of 4% PEG-6000 treatment reduced the total chlorophyll and carotenoids contents than that of 2% concentration in non-transgenic plantlets at 7 and 14 day after treatments (DAT). In addition, proline content and P5CS gene expression level in transgenic had been significantly increased during stress treatment. Based on these results, it can be concluded that the P5CS transgene increased the drought stress tolerance of oil palm.