Current Projects - Grey leaf spot disease of maize (see individual MPPI student project profiles)

  • Molecular basis of virulence in the fungus Cercospora zeina that causes GLS disease of maize
  • RNA interference (RNAi) for control of C. zeina
  • Population genomics of C. zeina on the African continent
  • Maize candidate genes for resistance and susceptibility to GLS disease
  • Impact of climate change on maize GLS disease
  • Maize tolerance to the fall armyworm pest

Completed Projects:

New Publications

Tembo M, Mahlangu JNN, Berger DK, Chimutingiza H, Chikoti PC, Prasanna BM, Suresh LM, Nsibo DL. (2024) First report of Bipolaris yamadae and Exserohilum rostrum associated with leaf spots of maize (Zea maydis) in Zambia. Plant Disease 108(9):2931. 10.1094/PDIS-05-24-1116-PDN
Nsibo DL, Barnes I, Berger DK. (2024) Recent advances in the population biology and management of maize foliar fungal pathogens Exserohilum turcicum, Cercospora zeina and Bipolaris maydis in Africa. Frontiers in Plant Science 15:1-23. https://doi.org/10.3389/fpls.2024.1404483
Marais I, Buitendag C, Duong TA, Crampton BG, Theron J, Kidanemarium D, Berger DK. (2024) Double-stranded RNA uptake for the control of the maize pathogen Cercospora zeina. Plant Pathology 73(6):1480-1490. 10.1111/ppa.13909
Abkallo HM, Arbuthnot P, Auer TO, Berger DK, Burger J, Chakauya E, Concordet J-P, Diabate A, Di Donato V, Groenewald J-H, Guindo A, Koekemoer LL, Nazare F, Nolan T, Okumu F, Orefuwa E, Paemka L, Prieto-Godino L, Runo S, Sadler M, Tesfaye K, Tripathi L, Wondji C. (2024) Making genome editing a success story in Africa. Nature Biotechnology :1-4. https://rdcu.be/dBJUa
Omondi DO, Dida MM, Berger DK, Beyene Y, Nsibo DL, Juma C, Mahabaleswara SL, Gowda M. (2023) Combination of Linkage and Association Mapping with Genomic Prediction to Infer QTL Regions Associated with Gray Leaf Spot and Northern Corn Leaf Blight Resistance in Tropical Maize. Frontiers in Genetics 14:1-16. 10.3389/fgene.2023.1282673
Welgemoed T, Duong TA, Barnes I, Stukenbrock EH, Berger DK. (2023) Population genomic analyses suggest recent dispersal events of the pathogen Cercospora zeina into East and Southern African maize cropping systems. G3 Genes|Genomes|Genetics 10.1093/g3journal/jkad214
Wingfield BD, Berger DK, Coetzee MPA, Duong TA, Martin A, Pham NQ, Van den Berg N, Wilken PM, Arun-Chinnappa KS, Barnes I, Buthelezi S, Dahanayaka BA, Durán A, Engelbrecht J, Feurtey A, Fourie A, Fourie G, Hartley J, Kabwe ENK, Maphosa M, Narh Mensah DL, Nsibo DL, Potgieter L, Poudel B, Stukenbrock EH, Thomas C, Vaghefi N, Welgemoed T, Wingfield MJ. (2022) IMA genome‑F17 Draft genome sequences of an Armillaria species from Zimbabwe, Ceratocystis colombiana, Elsinoë necatrix, Rosellinia necatrix, two genomes of Sclerotinia minor, short‑read genome assemblies and annotations of four Pyrenophora teres isolates from barley grass, and a long-read genome assembly of Cercospora zeina. 13:19. 10.1186/s43008-022-00104-3
Craze HA, Pillay N, Joubert F, Berger DK. (2022) Deep Learning Diagnostics of Gray Leaf Spot in Maize under Mixed Disease Field Conditions. Plants 11(1942):1-17. https://bit.ly/3vg484g
Luo G-F, Podolyan A, Kidanemariam D, Pilotti C, Houliston G, Sukal AC. (2022) A review of viruses infecting Yam (Dioscorea spp.). Viruses 14(662) 10.3390/v14040662
Nsibo DL, Barnes I, Omondi DO, Dida MM, Berger DK. (2021) Population genetic structure and migration patterns of the maize pathogenic fungus, Cercospora zeina in East and Southern Africa. Fungal Genetics and Biology 149(103527) 10.1016/j.fgb.2021.103527
Pillay N, Gerber M, Holan K, Whitham SA, Berger DK. 2021. Quantifying the Severity of Common Rust in Maize Using Mask R-CNN. In: Artificial Intelligence and Soft Computing. ICAISC 2021. Lecture Notes in Artificial Intelligence, vol 12854. Rutkowski L, Scherer R, Korytkowski M, Pedrycz W, Tadeusiewicz R, Zurada J. (eds). Springer, Cham., pp 202-213.
Aveling TAS, De Ridder K, Olivier NA, Berger DK. (2020) Seasonal variation in mycoflora associated with asymptomatic maize grain from small-holder farms in two provinces of South Africa. Journal of Agriculture and Rural Development in the Tropics and Subtropics (JARTS) 121(2):265-275. 10.17170/kobra-202011262275 PDF
Berger DK, Mokgobu T, De Ridder K, Christie N, Aveling TAS. (2020) Benefits of maize resistance breeding and chemical control against northern leaf blight in smallholder farms in South Africa. South African Journal of Science 12(11) 10.17159/sajs.2020/8286
Welgemoed T, Pierneef R, Read DA, Schulze SE, Pietersen G, Berger DK. (2020) Next generation sequencing reveals past and current widespread occurrence of maize yellow mosaic virus in South Africa. European Journal of Plant Pathology 158(1):237-249. 10.1007/s10658-020-02070-1
Human MP, Berger DK, Crampton BG. (2020) Time-course RNAseq reveals Exserohilum turcicum effectors and pathogenicity determinants. Frontiers in Microbiology 11(360) 10.3389/fmicb.2020.00360
Welgemoed T, Pierneef R, Sterck L, Van de Peer Y, Swart V, Scheepers KD, Berger DK. (2020) De novo assembly of transcriptomes from a B73 maize line introgressed with a QTL for resistance to gray leaf spot disease reveals a candidate allele of a lectin receptor-like kinase. Frontiers in Plant Science http://bit.ly/2SmKPmT
Devnarain N, Crampton BG, Olivier N, van der Westhuizen C, Becker JVW, O'Kennedy MM. (2019) Transcriptomic analysis of a Sorghum bicolour landrace identifies a role for beta-alanine betaine biosynthesis in drought tolerance.. South African Journal of Botany 127 10.1016/j.sajb.2019.08.049
Zumaquero A, Martinez-Ferri E, Matas AJ, Reeksting B, Olivier NA, Pliego-Alfaro F, Barcelo A, van den Berg N, Pliego C. (2019) Rosellinia necatrix infection induces differential gene expression between tolerant and susceptible avocado rootstocks. PLoS ONE 14(2):e0212359. 10.1371/journal.pone.0212359
Nsibo DL, Barnes I, Kunene NT, Berger DK. (2019) Influence of farming practices on the population genetics of the maize pathogen Cercospora zeina in South Africa. Fungal Genetics and Biology 125:36-44. 10.1016/j.fgb.2019.01.005
Read DA, Featherstone J, Rees DJG, Thompson GD, Roberts R, Flett BC, Mashingaidze K, Berger DK, Welgemoed T, Pietersen G, Schulze SE, Kiula B, Kullaya A, Mbega E. (2019) First report of maize yellow mosaic virus (MaYMV) on maize (Zea mays) in Tanzania. Journal of Plant Pathology 101:203. 10.1007/s42161-018-0152-5
van den Berg N, Mohamed W, Olivier NA, Swart V, Crampton B. (2018) Transcriptome analysis of an incompatible Persea americana-Phytophthora cinnamomi interaction reveals the involvement of SA- and JA-pathways in a successful defense response. PLoS ONE 13(10):e0205705. 10.1371/journal.pone.0205705
Viljoen E, Odeny DA, Coetzee MPA, Berger DK, Rees DJG. (2018) Application of Chloroplast Phylogenomics to Resolve Species Relationships Within the Plant Genus Amaranthus. Journal of Molecular Evolution 86(3-4):216-239. 10.1007/s00239-018-9837-9
Liversage J, Coetzee MPA, Bluhm BH, Berger DK, Crampton BG. (2018) LOVe across kingdoms: Blue light perception vital for growth and development in plant–fungal interactions. Fungal Biology Reviews 32(2):86-103. 10.1016/j.fbr.2017.11.003
Wingfield BD, Berger DK, Steenkamp ET, Lim H-J, Duong TA, Bluhm BH, De Beer ZW, De Vos L, Fourie G, Naidoo K, Olivier NA, Lin Y, Van der Peer Y, Joubert F, Crampton BG, Swart V, Soal N, Tatham C, Van der Nest MA, Van der Merwe NA, Van Wyk S, Wilken PM, Wingfield MJ. (2017) IMA Genome-F 8 Draft genome of Cercospora zeina, Fusarium pininemorale, Hawksworthiomyces lignivorus, Huntiella decipiens and Ophiostoma ips. IMA Fungus 8 (2):385‑396. 10.5598/imafungus.2017.08.02.10 PDF
Meyer J, Berger DK, Christensen SA, Murray SL. (2017) RNA-Seq analysis of resistant and susceptible sub-tropical maize lines reveals a role for kauralexins in resistance to grey leaf spot disease, caused by Cercospora zeina. BMC Plant Biology 17:197. 10.1186/s12870-017-1137-9
Amuge T, Berger DK, Katari MS, Myburg AA, Goldman SL, Ferguson ME. (2017) A time series transcriptome analysis of cassava (Manihot esculenta Crantz) varieties challenged with Ugandan cassava brown streak virus. Scientific Reports 7:9747. 10.1038/s41598-017-09617-z
Swart V, Crampton BG, Ridenour JB, Bluhm BH, Olivier NA, Meyer JJM, Berger DK. (2017) Complementation of CTB7 in the maize pathogen Cercospora zeina overcomes the lack of in vitro cercosporin production. Molecular Plant-Microbe Interactions 30(9):710-724. 10.1094/MPMI-03-17-0054-R
Zwart L, Berger DK, Moleleki LN, Van der Merwe NA, Myburg AA, Naidoo S. (2017) Evidence for salicylic acid signalling and histological changes in the defence response of Eucalyptus grandis to Chrysoporthe austroafricana. Scientific Reports 7:45402. 10.1038/srep45402 PDF
Christie N, Myburg AA, Joubert F, Murray SL, Carstens M, Lin Y-C, Meyer J, Crampton BG, Christensen SA, Ntuli JF, Wighard SS, Van de Peer Y, Berger DK. (2017) Systems genetics reveals a transcriptional network associated with susceptibility in the maize-gray leaf spot pathosystem. The Plant Journal 89(4):746-763. 10.1111/tpj.13419
Reitmann A, Berger DK, van den Berg N. (2017) Putative pathogenicity genes of Phytophthora cinnamomi identified via RNA-Seq analysis of pre-infection structures. European Journal of Plant Pathology 147(1):211-228. 10.1007/s10658-016-0993-8
Human MP, Barnes I, Craven M, Crampton BG. (2016) Lack of population structure and mixed reproduction modes in Exserohilum turcicum from South Africa. Phytopathology 106(11):1386-1392. 10.1094/PHYTO-12-15-0311-R
Muller MF, Barnes I, Kunene NT, Crampton BG, Bluhm B, Phillips S, Olivier NA, Berger DK. (2016) Cercospora zeina from maize in South Africa exhibits high genetic diversity and lack of regional population differentiation. Phytopathology 106(10):1194-1205. 10.1094/PHYTO-02-16-0084-FI
Oelofse D, Gazendam I, Veale A, Djami-Tchatchou A, Berger D, Dubery I. (2016) Functional characterization of a defense-related class-III chitinase promoter from Lupinus albus, active in legume and monocot tissues. European Journal of Plant Pathology 146(4):923-936. 10.1007/s10658-016-0970-2
Daru B, Berger DK, Van Wyk AE. (2016) Opportunities for unlocking the potential of genomics for African trees. New Phytologist 210:772-778. 10.1111/nph.13826
Meyer FE, Shuey LS, Ramsuchit S, Mamni T, Berger DK, van den Berg N, Myburg AA, Naidoo S. (2016) Dual RNA-sequencing of Eucalyptus nitens during Phytophthora cinnamomi challenge reveals pathogen and host factors influencing compatibility. Frontiers in Plant Science 7:191. 10.3389/fpls.2016.00191 PDF
Meyer J, Murray SL, Berger DK. (2016) Signals that stop the rot: Regulation of secondary metabolite defences in cereals. Physiological and Molecular Plant Pathology 94:156-166. 10.1016/j.pmpp.2015.05.011 PDF
Ronishree Magwanda, Lizahn Zwart, Nicolaas A. van der Merwe, Lucy Moleleki, Dave Kenneth Berger, Alexander A. Myburg, Sanushka Naidoo. (2016) Localization and Transcriptional Responses of Chrysoporthe austroafricana in Eucalyptus grandis Identify Putative Pathogenicity Factors. Front. Microbiol. 10.3389/fmicb.2016.01953
Carstens M, Berger DK. 2016. Biotechnology and Crop Disease Resistance in South Africa. In: Biotechnology for Plant Disease Control. Collinge DB. (eds). Wiley, New York and London, pp 16 (Chapter).
Reeksting B, Olivier N.A, van den Berg N. (2016) Transcriptome responses of an ungrafted Phytophthora root rot tolerant avocado (Persea americana) rootstock to flooding and Phytophthora cinnamomi. BMC Plant Biology 16(205) 10.1186/s12870-016-0893-2
Hussey SG, Mizrachi E, Groover A, Berger DK, Myburg AA. (2015) Genome-wide mapping of histone H3 lysine 4 trimethylation in Eucalyptus grandis developing xylem. BMC Plant Biology 15:117. 10.1186/s12870-015-0499-0 PDF
Mizrachi E, Maloney VJ, Silberbauer J, Hefer CA, Berger DK, Mansfield SD, Myburg AA. (2014) Investigating the molecular underpinnings underlying morphology and changes in carbon partitioning during tension wood formation in Eucalyptus. New Phytologist 204(6):1351-1363. 10.1111/nph.13152
Berger DK, Carstens M, Korsman JN, Middleton F, Kloppers FJ, Tongoona P, Myburg AA. (2014) Mapping QTL conferring resistance in maize to gray leaf spot disease caused by Cercospora zeina. BMC Genetics 15:60. 10.1186/1471-2156-15-60
Haasbroek MP, Craven M, Barnes I, Crampton BG. (2014) Microsatellite and mating type primers for the maize and sorghum pathogen, Exserohilum turcicum. Australasian Plant Pathology 43(5):577-581. 10.1007/s13313-014-0289-4 PDF
Phillips S, Dubery I, Heerden H. (2013) Molecular characterisation of two homoeologous elicitor-responsive lipin genes in cotton. Molecular Genetics and Genomics 288:519-533. 10.1007/s00438-013-0770-8
Van der Linden L, Bredenkamp J, Naidoo S, Fouche-Weich J, Denby KJ, Genin S, Marco Y, Berger DK. (2013) Gene-for-Gene Tolerance to Bacterial Wilt in Arabidopsis. Molecular Plant-Microbe Interactions 26:398-406. 10.1094/MPMI-07-12-0188-R
Phillips S, Dubery I, Heerden H. (2013) Identification and molecular characterisatin of a Lectin Receptor-like Kinase (GhLecRK-2) from cotton. Plant Molecular Biology Reporter 31(1):9-20. 10.1007/s11105-012-0470-2
Naidoo R, Ferreira L, Berger DK, Myburg AA, Naidoo S. (2013) The identification and differential expression of Eucalyptus grandis pathogenesis-related genes in response to salicylic acid and methyl jasmonate. Frontiers in Plant Science 4:43. 10.3389/fpls.2013.00043
Phillips SM, Dubery IA, van Heerden H. (2012) Molecular characterization of an elicitor-responsive Armadillo repeat gene (GhARM) from cotton (Gossypium hirsutum). Molecular Biology Reports 39:8513-23. 10.1007/s11033-012-1706-9
Van Schalkwyk A, Wenzl P, Smit S, Lopez-Cobollo R, Kilian A, Bishop G, Hefer C, Berger D. (2012) Bin mapping of tomato diversity array (DArT) markers to genomic regions of Solanum lycopersicum X Solanum pennellii introgression lines. Theoretical and Applied Genetics 124:947-956. 10.1007/s00122-011-1759-5
Korsman J, Meisel B, Kloppers F, Crampton B, Berger D. (2012) Quantitative phenotyping of grey leaf spot disease in maize using real-time PCR. European Journal of Plant Pathology 133:461-471. 10.1007/s10658-011-9920-1
Hussey SG, Mizrachi E, Spokevicius AV, Bossinger G, Berger DK. (2011) SND2, a NAC transcription factor gene, regulates genes involved in secondary cell wall development in Arabidopsis fibres and increases fibre cell area in Eucalyptus. BMC Plant Biology 11:173. 10.1186/1471-2229-11-173
Coetzer N, Myburg AA, Berger DK. (2011) Maize microarray annotation database. Plant Methods 7(31) 10.1186/1746-4811-7-31
Hussey S, Mizrachi E, Berger D, Myburg AA. (2011) The role of SND2 in the regulation of Arabidopsis fibre secondary cell wall formation. BMC Proceedings 5(7):P114. 10.1186/1753-6561-5-S7-P114
Naidoo S, Fouche-Weich J, Law P, Denby KJ, Marco Y, Berger DK. (2011) A Eucalyptus bacterial wilt isolate from South Africa is pathogenic on Arabidopsis and manipulates host defences. Forest Pathology 41:101-113. 10.1111/j.1439-0329.2010.00642.x
Coetzer N, Gazendam I, Oelofse D, Berger DK. (2010) SSHscreen and SSHdb, generic software for microarray based gene discovery: application to the stress response in cowpea. Plant Methods 6(10)
Solomon OL, Berger DK, Myburg AA. (2010) Diurnal and circadian regulation of carbon allocation in developing xylem of Eucalyptus trees. South African Journal of Botany 76:425-439. 10.1016/j.sajb.2010.02.087
Coetzer N, Gazendam I, Oelofse D, Berger DK. (2010) SSHscreen and SSHdb, generic software for microarray based gene discovery: application to the stress response in cowpea. Plant Methods 6:10. 10.1186/1746-4811-6-10
Legay G, Marouf E, Berger D, Neuhaus JM, Mauch-Mani B, Slaughter A. (2010) Identification of genes expressed during the compatible interaction of grapevine with Plasmopara viticola through suppression subtractive hybridization (SSH). European Journal of Plant Pathology 129:281-301. 10.1007/s10658-010-9676-z
Solomon OL, Berger DK, Myburg AA. (2010) Diurnal and circadian patterns of gene expression in the developing xylem of Eucalyptus trees. South African Journal of Botany 76:425-439. 10.1016/j.sajb.2010.02.087
Crampton BG, Hein I, Berger DK. (2009) Salicylic acid confers resistance to a biotrophic rust pathogen, Puccinia substriata, in pearl millet (Pennisetum glaucum). Molecular Plant Pathology 10:291-304.
Meisel B, Korsman J, Kloppers F, Berger DK. (2009) Cercospora zeina is the causal agent of grey leaf spot disease of maize in southern Africa. European Journal of Plant Pathology 124:577-583. 10.1007/s10658-009-9443-1
van den Berg N, Berger DK, Hein I, Birch PRJ, Wingfield MJ, Viljoen A. (2009) Genes up-regulated in tolerant cavendish banana roots in response to Fusarium oxysporum f. sp. cubense infection. Acta Horticulturae 828:273-282. PDF
Creux NM, Ranik M, Berger DK, Myburg AA. (2008) Comparative analysis of orthologous cellulose synthase promoters from Arabidopsis, Populus and Eucalyptus: evidence of conserved regulatory elements in angiosperms. New Phytologist 179:722-737. 10.1111/j.1469-8137.2008.02517.x
Law P, Claudel-Renard C, Joubert F, Louw A, Berger D. (2008) MADIBA: A web server toolkit for biological interpretation of Plasmodium and plant gene clusters. BMC Genomics 9:105.
Naidoo S, Murray SL, Denby KJ, Berger DK. (2007) Microarray analysis of the Arabidopsis thaliana cir1 (constitutively induced resistance 1) mutant reveals candidate defence response genes against Pseudomonas syringae pv tomato DC3000. South African Journal of Botany 73:412-421.
van den Berg N, Berger DK, Hein I, Birch PRJ, Wingfield MJ, Viljoen A. (2007) Tolerance in banana to Fusarium wilt is associated with early up-regulation of cell wall-strengthening genes in the roots. Molecular Plant Pathology 8(3):333-341. 10.1111/j.1364-3703.2007.00389.x PDF
Fouche-Weich J, Berger D, Poussier S, Trigalet-Demery D, Coutinho T. (2006) Molecular identification of some African strains of Ralstonia solanacearum from eucalypt and potato. Journal of General Plant Pathology 72:369-373.
Oelofse D, Dubery IA, Meyer R, Arendse MS, Gazendam I, Berger DK. (2006) Apple polygalacturonase inhibiting protein1 expressed in transgenic tobacco inhibits polygalacturonases from fungal pathogens of apple and the anthracnose pathogen of lupins. Phytochemistry 67:255-263.
Lotter HC, Berger DK. (2005) Anthracnose of lupins in South Africa in caused by Colletotrichum lupini var. setosum. Australasian Plant Pathology 34:385-392.
Naidoo S, Denby KJ, Berger DK. (2005) Microarray experiments: considerations for experimental design. South African Journal of Science 101:347-354.
Gazendam I, Oelofse D, Berger DK. (2004) High-level expression of apple PGIP1 is not sufficient to protect transgenic potato against Verticillium dahliae. Physiological and Molecular Plant Pathology 65:145-155.
Lezar S, Myburg AA, Berger DK, Wingfield MJ, Wingfield BD. (2004) Development and assessment of microarray-based DNA fingerprinting in Eucalyptus grandis. Theoretical and Applied Genetics 109(7):1329-1336. 10.1007/s00122-004-1759-9 PDF
Crampton BG, van den Berg N, Hein I, Birch PRJ, Berger DK. (2004) High-throughput screening of suppression subtractive hybridization cDNA libraries using DNA microarray analysis. BioTechniques 37(5):818-824.
Bhoora R, Berger DK, Wingfield MJ, Wingfield BD. (2003) PCR cloning by genome walking of a complete polygalacturonase-inhibiting protein gene from Eucalyptus grandis. South African Journal of Science 99(9-10):410-412. PDF
Murray SL, Denby KJ, Berger DK, Loake GJ. (2002) Disease resistance signalling in Arabidopsis: Applications in the study of plant pathology in South Africa. South African Journal of Science 98
Botha WJ, Serfontein S, Greyling MM, Berger DK. (2001) Detection of Xylophilus ampelinus in grapevine cuttings using a nested polymerase chain reaction. Plant Pathology 50:515-526.
O'Kennedy MM, Burger JT, Berger DK. (2001) Transformation of elite white maize using the particle inflow gun and detailed analysis of a low-copy integration event. Plant Cell Reports 20:721-730.
Berger DK, Oelofse D, Arendse MS, du Plessis E, Dubery IA. (2000) Bean polygalacturonase inhibitor protein-1 (PGIP-1) inhibits polygalacturonases from Stenocarpella maydis. Physiological and Molecular Plant Pathology 57:5-14.
De Villiers SM, Kamo K, Thomson JA, Bornman CH, Berger DK. (2000) Biolistic transformation of Chincherinchee (Ornithogalum) and regeneration of transgenic plants. Physiologia Plantarum 109:450-455.
Murray SL, Van Vuuren RJ, Berger DK. (1998) Tomato transformation is dependent upon Agrobacterium cell density and acetosyringone levels. Journal of the Southern African Society for Horticultural Sciences 8:60-64.
Murray SL, Burger JT, Oelofse D, Cress WA, Van Staden J, Berger DK. (1998) Transformation of potato (cv. Late Harvest) with the potato leafroll virus coat protein gene, and molecular analysis of transgenic lines. South African Journal of Science 94:263-268.
Berger DK, Narberhaus F, Lee HS, Kustu S. (1995) In vitro studies of the domains of the nitrogen fixation regulatory protein NifA. The Journal of Bacteriology 177:191-199.
Berger DK, Narberhaus F, Kustu S. (1994) The isolated catalytic domain of NifA, a bacterial enhancer-binding protein, activates transcription in vitro: activation is inhibited by NifL. PNAS 91:103-107.
Kilkenny CA, Berger DK, Rawlings DE. (1994) Isolation of the Thiobacillus ferrooxidans ntrBC genes using a T. ferrooxidans nifH-lacZ fusion. Microbiology 140:2543-2553.
Lee HS, Berger DK, Kustu S. (1993) Activity of purified NIFA, a transcriptional activator of nitrogen fixation genes. PNAS 90:2266-2270.
Santero E, Hoover TR, North AK, Berger DK, Porter SC, Kustu S. (1992) Role of integration host factor in stimulating transcription from the sigma 54-dependent nifH promoter. Journal of Molecular Biology 227:602-620.
Berger DK, Woods DR, Rawlings DE. (1990) Complementation of Escherichia coli sigma 54 (NtrA)-dependent formate hydrogenlyase activity by a cloned Thiobacillus ferrooxidans ntrA gene. Journal of Bacteriology 172:4399-4406.