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P1. Screening of U.S. Germplasm for Resistance to Peanut Smut

K.D. Chamberlin 1, R.S.Bennett1, J. Baldessari.2, C.C. Holbrook3, S.P. Tallury4, J. Clevenger5 and P. Ozias-Akins, P 6.

1USDA ARS, Stillwater, OK

2INTA, Manfredi, Argentina

3USDA ARS, Tifton, GA

4USDA ARS Griffin, GA

5MARS WRIGLEY Confectionery

6University of Georgia, Tifton, GA

Peanut smut, caused by Thecaphora frezzii, was first reported in Brazil, but has since spread to other countries including Argentina where it has become established and is now found in 100% of the country’s peanut growing regions. Disease severity varies with location, but yield reductions as high as 51% have been reported. Although peanut smut is not currently found in the U.S., immediate proactive measures will ensure that the industry will not be threatened should this disease reach the U.S. The first step in breeding efforts for peanut smut is to identify sources of resistance.  Therefore, the objective of this study was to identify sources of resistance to T. frezzii that can be used to incorporate smut resistance into cultivars optimized for key areas of U.S. peanut production. In 2017, 106 genotypes, including mini-core accessions from the USDA Peanut Germplasm collection and a selection of U.S. elite breeding lines and cultivars, were planted in a test plot with high levels of T. frezzii inoculum near the town of General Deheza (Córdoba Province).  Plots were arranged in an augmented grid design with three replicates and were maintained for weeds and other diseases throughout the growing season.  Upon harvest, pods were air dried and opened by hand to rate for the presence or absence of T. frezzii.  For screening purposes, entries were retained for further testing if they scored 10% or less disease incidence. Of the 106 test entries, 35 potential sources of peanut smut resistance were identified. Thirteen entries had 0% disease incidence, 9 entries had between 0 and 5% disease incidence, and 13 entries had between 5% and 10% disease incidence. Seventy-one (71) of the entries tested had greater than 10% disease incidence and have been eliminated from future testing.  Entries demonstrating strong resistance over multiple years can be used to incorporate peanut smut resistance into cultivars suitable for U.S. production areas.

Email:  Kelly.Chamberlin@ARS.USDA.GOV

P2. Integrated small RNA and mRNA Expression Profiles Reveals miRNAs and Their Target Genes in Response to Aspergillus flavus Infection in Peanut Seeds

Chuanzhi Zhao1, Tingting Li1, Lei Hou1, Han Xia1, Aiqin Li1, Shuzhen Zhao1, Pengcheng Li, Baozhu Guo2, Xingjun Wang1,2*

1 Biotechnology Research Center, Shandong Academy of Agricultural Sciences; Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Ji’nan 250100, PR China.

2 USDA-Agricultural Research Service, Crop Protection and Management Research Unit, Tifton, GA 31793, USA

Peanut is vulnerable to the threat of aflatoxin contamination. The molecular basis between peanut and A. flavus compatible interaction is elusive. MicroRNAs have been found to be an important regulator of plant immune system. Here, we employed small RNA, transcriptome and degradome sequencing approaches to systematically investigate the regulatory roles of miRNAs in resistant and susceptible genotypes of peanut under fungus infection. A total of 30 miRNAs, 447 genes and 21 miRNA/mRNA pairs were differentially expressed significantly after infected with A. flavus. Moreover, a total of 62 miRNAs, 451 genes and 44 miRNA/mRNA pairs exhibited differential expression profiles between resistant and susceptible genotypes. GO analysis showed that metabolic-process related GO terms were enriched, such as “metabolic process” and “catalytic activity”. KEGG pathway analysis further supported the GO results, in which the majority of enriched pathways were related to biosynthesis and metabolism, such as “biosynthesis of secondary metabolites”, and “metabolic pathways”. Correlation analysis of small RNA, transcriptome and degradome results indicated that the differential expressed miR156/SPL pairs regulated the accumulation of flavonoids in resistant and susceptible genotypes. The miR482/2118 family regulated NBS-LRR defense genes, such as Aradu.168L7, which has the higher expression level in resistant genotype when compared with that in susceptible genotype. These results suggested that both miR156/157/SPL and miR482/2118/NBS-LRR pairs play crucial roles in peanut-A. flavus interaction and lead the difference resistance between two varieties. In summary, our study provides a comprehensive information for our understanding of peanut-A. flavus interaction.


P3. Assessing INTA’s Arachis hypogaea Core Collection for Reaction to Peanut Smut

EMC Mamaní1, AV Rodríguez1, G Cordes1, CDP Díaz1, MV Moreno1, VJ Etchart2, G. de la Barrera1 & J Baldessari1

1National Institute for Agricultural Technology (INTA), Manfredi Exp. Stn., Manfredi (5988), Argentina.

2INTA, IGEAF, CICVyA, Hurlingham (1686), Argentina

There is a high intensity of peanut smut in Argentina’s main peanut area. As chemical control and crop rotation have shown modest results controlling the disease, genetic resistance appears a more promising approach. Thus, increased efforts to detect sources of genetic resistance to Thecaphora frezzii are needed. INTA’s Manfredi Exp. Stn. developed a Core Collection of A. hypogaea (CNM) that includes entries from the six botanical varieties and its entries account for a 4% of the total entries in the entire Manfredi Peanut Collection. Molecular analysis showed that the genetic diversity in CNM is high (0.61). Population structure was inferred through Bayesian analysis. Highest data probability was attained at K=2 suggesting entries can be assigned to two groups coinciding with the subspecies taxonomic level. Lack of structure within each group was also observed implying CNM has great potential for association mapping for peanut smut. Additionally, two years of seed increase of an association mapping population (made out of a single plant from each entry in the CNM) has been done. Seeds from each plant in this population along with resistance and susceptible checks were assessed in a heavily smut infested field in General Deheza, Province of Córdoba, Argentina. Augmented grid design (akin to Early Generation Variety Trials Designs) was used by placing experimental units in a 2D layout (row-column). Experimental units were individual plants of each entry in the mapping population. R & S checks were deployed diagonally across the test. Smut resistance was assessed by estimating “smut incidence” as a ratio “infected pods/total pods”. First season results (summer 2017-18) show some entries display resistant reaction similar to the resistant standard. GLMM models are being adjusted for better analysis of the data obtained during the first season. Additionally, DNA samples for each entry were extracted for genotyping with Axiom Arachis2 (58 K SNP array) thus increasing the likelihood of finding alleles for smut resistance.


P4. Tracking of Wild Allele Introgressions in a Peanut Chromosome Segment Substitution Line Population

D.Gimode *1, Y. Chu2, Bertioli S3., D. Bertioli3, C. Holbrook4, J. Clevenger5, L. Dean6, D. Fonceka7, and P. Ozias-Akins1

1Institute of Plant Breeding Genetics and Genomics, University of Georgia, Tifton, GA 31793. 2Department of Horticulture, University of Georgia, Tifton GA 31793

3Center for Applied Genetic Technologies, University of Georgia, Athens GA 30606

4United States Department of Agriculture -Agricultural Research Service, Tifton GA 31793

5Mars Wrigley Confectionery, Center for Applied Genetic Technologies, Athens, GA 30606

6USDA-ARS,  Raleigh NC 27695

7Centre d’Etudes Régional pour I’Amélioration de I’Adaptation à la Sécheresse, Thies, Senegal

Cultivated peanut arose from the hybridization of the diploids Arachis duranensis (A genome progenitor) and Arachis ipaensis (B genome progenitor), followed by spontaneous chromosome doubling to yield the current allotetraploid state (AABB; 2n=4x=40).  This genetic heritage, short period since polyploidization, self-pollinating breeding system, and domestication bottleneck have resulted in a crop with reduced diversity. In order to harness polymorphism from its wild relatives, a chromosome segment substitution line (CSSL) population was created via the tetraploid route to interspecific hybridization. The CSSL population was derived by crossing the A and B genome progenitors, doubling the chromosomes of the cross, and introgressing chromosome segments from the resultant synthetic allotetraploid into the background of a cultivated variety (Fleur 11). Through SNP genotyping, we have developed high-resolution sets of markers that have enabled us to precisely delineate the regions of wild genetic introgression. In addition, we have observed evidence of tetrasomic recombination events in the population. By comprehensively phenotyping the population, we have uncovered significant variation in canopy, below ground, as well as seed composition traits. Analysis of the genotype and phenotype data has enabled us to propose how chromosome segments from the wild may alter the expression of traits in the cultivated genetic background. This study improves our understanding of how the wild relatives of peanut can be used to confer beneficial traits to cultivated peanut varieties.


P5. Global methylome and Gene Expression Analysis During Early Peanut Pod Development

Han Xia1,3, Pengfei Wang1,2, Chuanzhi Zhao1,3, Lei Hou1, Lin Zhu1,3, Xingjun Wang1,3*

1 Biotechnology Research Center, Shandong Academy of Agricultural Sciences; Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Ji’nan 250100, PR China

2 Shandong Academy of Grape, Ji’nan 250100, PR China

3 College of Life Sciences, Shandong Normal University, Ji’nan 250014, PR China

Early development of peanut pod is an important process of peanut yield development. DNA methylation modes during early peanut pod development are still unclear now. To investigate the functions of the dynamic DNA methylation during peanut early pod development, global methylome and gene expression analysis were carried out by MeDIP-seq and Illumina high throughput sequencing. Differentially methylated genes were identified during three stages, S1, S2 and S3 of early peanut pod development, for examples, nodulin, cell number regulator-like protein, and senescence-associated genes. The expression levels of many gibberellins-related genes were changed during this period of pod development. From S1 to S2 gynophore, expression levels of two key methyltransferase genes, DRM2 and MET1, were up-regulated, which may lead to global DNA methylation changes between these two stages. The differentially methylated and expressed genes identified in S1, S2 and S3 gynophores involved in different biological processes, such as stem cell fate determination, response to red, blue and UV light, post-embryonic morphogenesis, and auxin biosynthesis. The expression levels of many genes were co-related to their DNA methylation levels. In addition, our results showed that the abundance of some 24-nt siRNAs and miRNAs were positively associated with DNA methylation levels of their target loci in peanut pods. The identified methylation changes during peanut early pod development provide useful information for understanding the roles of epigenetic regulation in peanut pod development.


P6. Assessing the Genetic Diversity of 15 Groundnut (Arachis hypogaea L.) Genotypes Among Which the Most Widely Cultivated Varieties in Senegal

Issa FAYE1*, Amy BODIAN2 and Daniel FONCEKA3

1ISRA-CNRA, Peanut   Breeding and Genetics Laboratory, PoBox 53 Bambey (Senegal)

2ISRA-CERAAS, PoBOX 3120 Thiès (Senegal)

3ISRA-CERAAS-CIRAD, PoBOX  3120 Thiès (Senegal)

Groundnut (Arachis hypogaea L.) is the most important grain legume in Senegal. However, its production is constrained by a myriad of biotic and abiotic stresses which necessitate the development and use of superior varieties for increased yield. Germplasm characterization both at the phenotypic and molecular level is important in all plant breeding programs. The aim of this study was to characterize 15 selected advanced breeding groundnut lines with different phenotypic attributes using simple sequence repeats (SSR) markers. The selected lines are contrasting for different traits including drought tolerance, pre-harvest aflatoxin contamination, seed quality traits, earliness, diseases resistance and yield. A total of 300 SSR markers were screened and hundred and sixty SSR markers were found polymorphic. The averaged mean of alleles per a locus was 3 alleles while the highest number of alleles per locus was 7. The markers TC11H06, Seq19D06, IPAHM103, Seq9A07, Seq14H06, Seq3A08, TC25G11, Seq15C10, TC27H12, TC23H09, Seq9A08 and PM050 were the most polymorphic markers revealing a least 5 alleles among the panel of genotyped lines. These highly polymorphic markers are being used for background and foreground selection to advance new populations.


P7. A Comparative Analysis of the Complete Chloroplast Genome Sequences of Four Peanut Botanical Types

Juan Wang*, Chunjuan Li*, Caixia Yan, Xiaobo Zhao, Shihua Shan

Laboratory of Genetics and Breeding, Shandong Peanut Research Institute, Qingdao, China

Arachis hypogaea L. is an economically important oilseed crop worldwide and there are in total six botanical varieties within this species that have considerable morphological and molecular differences. The available chloroplast genome data within species is still limited. The complete chloroplast (cp) genome sequences of four representative botanical varieties (var. hypogaea. var. hirsuta, var. fastigiata and var. vulgari) were obtained by next-generation sequencing (NGS). The high throughput sequencing data were assembled, annotated and comparative analyzed. The total cp genome lengths of the studied A. hypogaea were 156,354 bp (for var. hypogaea), 156,878bp (for var. hirsuta), 156,718bp (for var. fastigiata) and 156,399bp (for var. vulgaris), respectively. Comparative cp genome sequence analysis of these four types revealed that their gene content, gene order and GC content were highly conserved, with only a total of 46 SNPs and 26 InDels identified among them. Most of these variation is restricted to non-coding sequences, especially, the highly variable region (trnI-GAU intron) was detected and will be useful for future evolutionary studies. These four cp genome sequences acquired here will provide valuable genetic resources for distinguishing A. hypogaea botanical types and determining the genetic relationship.


P8. Peanut Mutant Induction, Screening and Utilization

Lei Hou1, Chuanzhi Zhao1, Han Xia1, Junjie Ma1,2, Fengdan Guo1,3, Xingjun Wang1,2,3*

1 Biotechnology Research Center, Shandong Academy of Agricultural Sciences; Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan 250100, PR China.

2 Life Science College of Shandong University, Jinan 250100, PR China. 3 College of Life Sciences, Shandong Normal University, Jinan 250014, PR China

Germplasms innovation through mutagenesis is an important way for crop genetic improvement and gene functional analysis. Peanut mutant population was generated by treating mature seeds of 12 cultivars from China and the United States, including 10 erect type and 2 spreading type peanuts, with EMS, 60Co γ ray and fast neutron. Totally, more than 60, 000 M1 lines were obtained. M2 lines with different phenotypes from the parental cultivars were grown to generate M3 plants for further confirmation of the mutant phenotypes. Through screening of more than 30, 000 lines, a large number of mutants with stable phenotypes were identified, for example, mutants with high protein contents, high oil contents, high oleic acid contents, more branches, dwarf, big and small fruits, shrinking seed, crack seed coat, purple seed coat, shortened dormancy period, and late maturity. Currently, a small seeded mutant and a semi-dwarf mutant were used for further study. These mutants were used to cross with the parental cultivars to generate F1 and then constructed F2 populations. F2 populations were used to identify genes that caused the phenotypes by BSA sequencing and map-based cloning. Digital gene expression profiles of mutants and wild types plants were carried out to understand the global influence of the mutated genes. A large number of genes were found to be differentially expressed in the mutants compare with the wild type controls. The contents of endogenous hormones including GA, IAA and ABA in the mutants and the wild type plants were also analyzed.


P9. Using an Interspecific Population to Improve Biological Nitrogen Fixation of Cultivated Peanut (Arachis hypogaea L.)

  1. Nzepang1, 2, 4, A. Zaïya Zazou1,2,3, S. Fall1, 2, D. Fonceka4, 6 and S. Svistoonoff1, 2, 5

1 LCM (IRD/ISRA/UCAD), Dakar, Senegal

2 LMI LAPSE, Dakar, Senegal

3 IRAD, Yaounde, Cameroon

4 CERAAS, Thiès Senegal

5 UMR LSTM (IRD/CIRAD/INRA/Université Montpellier/Supagro), Montpellier, France

6 CIRAD, UMR AGAP, Montpellier, France

Biological nitrogen fixation (BNF) is an important economic and environmental process, which remains integrated in legumes breeding programs. Groundnut (Arachis hypogaea L.) is an allotetraploid grain legume cultivated for oil and food uses. Groundnut is mainly cultivated by poor farmers in Africa without fertilizers and in soil with low fertility, showing particularly N and P deficiency. Improving biological nitrogen fixation in groundnut could be of great interest to increase yield and lift-up soil fertility. In this study we used an interspecific mapping population to identify quantitative trait loci (QTLs) involved in BNF traits in groundnut. A subset of 83 chromosome segment substitution lines (CSSLs) developed at CERAAS by crossings between a synthetic tetraploid AiAd (A. ipaensis × A. duranensis) and cultivated variety Fleur 11 was evaluated for BNF under glasshouse conditions. Three conditions were tested: – N, + N and – N + inoculation with an efficient Bradyrhizobium strain (ISRA 400). BNF traits such as chlorophyll content, shoot and root dry weight were recorded. A significant variation of response to inoculation was observed for all traits and a significant positive relationship was found between chlorophyll content and biomass traits. A total of 25 QTLs were mapped only in inoculated condition for BNF traits whose positive or negative effects were associated with alleles of the wild parents. These results suggest new possibilities to improve BNF using wild species and could be exploited to understand the genetic mechanism of BNF in groundnut.


P10. Toward fine-mapping of a wild genomic region involved in seed size reduction on chromosome A07 in peanut (Arachis hypogaeaL.)

J. Pallu, M.H. Alyr, T. Hodo-Abalo, M. Seye, D. Sane, J.F. Rami, and D. Fonceka

P11.  DNA menthylation pattern among the diverse genotypes of peanut (Arachis hypogaea L.)

R.S Bhat, J. Rockey, Kenta Shirasawa, I.S. Tilak, M.P. Brijesh Patil, and V.B Reddy

P12. Investigating the potential of the wild species A. valida to enlarge the cultivated peanut genetic basis

Sambou A., J.R. Nguepjob, H.A. Tossim, M. Seye, S. Sharma, N. Mallikarjuna, B.E. Ifie, P.B. Tongoona, D. Bertioli, S. Leal-Bertioli, Y. Chu, P. Ozias-Akins, and D. Fonceka

P13. Can pod and seed size be improved by pyramiding wild QTLs alleles in cultivated peanut?

H.A. Tossim, J.R. Nguepjob, A. Sambou, M. Seye, R.I. Djiboune, J.F. Rami, D. Sane, and D. Fonceka

P14. Evaluation of 36 peanut varieties for adaptability, pod yield and resistances to foliar disease in Burkina Faso

M. Konaté, A. Zongo, J. Sanou, Z. Sekone, H. Tapsoba, P. Janila, and H. Desmae

P15. Insights on the composition and evolution of the satellitome in the A and B Arachis genomes 

S. Samoluk, M. Vaio, L. Chalup, G. Robledo, D. Bertioli, S. Jackson, and G. Seijo

P16. MultI-resitant RILs Population assessed for Peanut Blight caused by Sclerotinia minor.

M. Rosso, F. de Blas, M. Bressano, M. Buteler, J. Soave, S. Soave, G.Y. Seijo, and C. Oddino

P17. Graph-based clustering and characterization of rDNA genes of allotetraploid species of Arachis section (peanut and A. monticola) and their diploid parentals by next-generation sequencing

Chalup L, Samoluk SS, Agostini F, Robledo G, Seijo

P18. Nourishing groundnut productivity: Case of the commu+C98:D114nity seed bank and farmer research network technology transfer models in Malawi

Mwololo, J., W. Munthali, F. Sichali, C. Harvey, L. Kachulu, F. Mataya, L. Shumba, and P. Okori

P19. Molecular diversity and marker-trait association for resistance to foliar fungal diseases and nutritional quality traits in Genomic Selection Training Population of Groundnut

Sunil Chaudhari, D. Khare, Murali T. Variath, Manish K. Pandey, and P. Janila

P20. Fatty acid accumulation in ahFAD mutant high oleic groundnut lines across developmental stages and its effect on seed quality parameters

Dnyaneshwar Deshmukh, T.V. Murali, Balram Marathi, Sunil Chaudhari, Pooja M. Bhatnagar, and P. Janila

P21. Genetic variability for resistance to peanut bud necrosis disease in a recombinant inbred line population of groundnut (Arachis hypogaea L.) 

Yashoda, Surendra S. Manohar, Gururaj Sunkad, K.P. Viswanatha, Manish K. Pandey, Murali T. Variath, Yaduru Shasidhar, Praveen Kona, Rajeev K. Varshney, and P. Janila

P22.  Relative ranking and risk to sustainability of pest management tools in the Virginia-Carolina region of the United States

David Jordan, Rick Brandenberg, Barbara Shew, Dan Anco, Mike Marshall, Hillary Mehl, Sally Taylor, Maria Balota, Jeffrey Dunne, and Thomas Stalker

P23.  Association of pod shell thickness and kernel weight with shelling outturn in a MAGIC population of groundnut 

Su Htwe Nge, Khin Mar Mar Nwe, Maw Maw Niang, Sunil Chaudhari, Dnyneshwer Deshmukh, and P. Janila

P24.  A survey of physiological and genetic responses of Arachis species to water deficit

D.R.S. Leal, A.R.M. Chaves, S.T. Aidar, A.C.G. Araujo, and C.V. Morgante

P25.  Brazilian Indian landraces of Arachis hypogaea: Cytogenetic evidences of its origin

E.F.M.B. Nascimento, F.O. Freitas, J.F.M. Valls, P.M. Guimarães, and A.C.G Araujo

P26. Proteomic analysis of Arachis stenosperma and Meloidogyne arenaria interaction 

A.C.Q. Martins, A.P.Z. Mota, M.A.P. Sariva, A.M. Murad, A. Mehta, A.C.M. Brasilerio, A.C.G. Araujo, R.N.G. Miller, and P.M. Guimarães

P27.  Selection of lines related to the wild parents with useful variability for the peanut breeding program in Brazil

T.M.F. Suassuna, N.D. Suassuna, S.C.M. Leal-Bertioli, D.J. Bertioli, J. Heubert, K.B.B. Martins, M.C. Moretzsohn

P28.  Development of peanut lines that incorporate resistances to leafspots and root-knot nematode from Arachis wild species

A.R. Custódio, J.F. Santos, A.R.A. Moraes, I.J.Godoy, M.D. Michelotto, S.C.M. Leal-Bertioli, D.J. Bertioli, M.C. Moretzsohn

P29. Cytogenetic characterization of new induced allotetraploids of Arachis

Eliza F. de M. B. do Nascimento, Dongying Gao, Patrícia M. Guimarães, Ana C. M. Brasileiro, Soraya C. M. Leal-Bertioli, David J. Bertioli, Ana C. G. Araujo

P30. Evaluation of Root-knot nematode resistance from the peanut wild relative Arachis stenosperma incorporated in allotetraploid backcrossed lines 

Carolina Ballén Taborda, Ye Chu, Scott A. Jackson, Peggy Ozias-Akins, C Corley Holbrook, David J. Bertioli1 and Soraya C.M. Leal-Bertioli

P31. Development of a high-density genetic map based on the specific length amplified fragment sequencing and its application in quantitiative trait loci analysis for yield-related traits in cultivated peanut

Zhihui Wang, Dongxin Huai, Zhaohua Zhang, Ke Cheng, Yanping Kang, Liyun Wan, Liying Yan, Huifang Jiang, Boshou Liao, and Yong Lei

P32. Discovery of genomic regions and candidate genes for stable QTLs controlling shelling perentage using QTL-seq approach in cultivated peanut (Arachis hypogaea L.)

Huaiyong Luo, Manish K. Pandey, Aamir W. Khan, Yong Lei, Boshou Liao, Rajeev K. Varshney, and Huifang Jiang

P33.  Identification and functional analysis of the KCS gene family in peanut (Arachis hypogaea L.)

Dongxin Huai, Xiaomeng Xue, Zhaohua Zhang, Zhihui Wang, Liying Yan, Liyun Wan, Huifang Jiang, Yong Lei, and Boshou Liao

P34.  Identification of genomic regions and diagnostic markers for resistance to aflatoxin contamination in peanut (Arachis hypogaea L.)

Bolun Yu, Dongxin Huai, Yong Lei, Manish K. Pandey, Hari Sudini, Rajeev K. Varshney, Boshou Liao, and Huifang Jiang