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resolved these to 54 species in 31 genera high disease whereas barley planted afer Proteobacteria Acidobacteria Chloroflexi
A comparison of the taxa identified in the sorghum­sudangrass or the phacelia/brown and Actinobacteria were found to be the most
present study as compared to those reported mustard mix had low disease incidence Sim­ abundant in the crop's rhiZosphere Fortifying
in five metagenomic studies revealed similar­ ilarly soybean planted afer alfalfa or oilseed garlic residue with chemical fertiliZer helps to
ities However of the 31 genera we identified radish consistently had high disease whereas sequester carbon but does not improve soil
by sequencing 18 genera (52%) were not soybean planted afer phacelia had low dis ­ bacterial community and vegetable yield
reported in the metagenomic studies The five ease incidence FRCR obser ved in the GH trial
metagenomic studies identified an average of was also significantly afected by preceding 67. How oomycete community structure
44 genera with 46% being unique to a partic­ cover crop Results indicate that certain cover responds to crop rotation and tillage
ular study and this ranged from 4% to 72% in crops afect root disease in subsequent crops A C GAHAGAN S ARIS­BROSOU M J MORRI­
the diferent studies In addition to revealing by influencing the microbial composition in SON AND W CHEN Agriculture and Agri-Food
genera which were not reported in other stud­ the soil and that sorghum­sudangrass may Canada, 960 Carling Ave., Ottawa, ON K1A 0C6,
ies an advantage of full length ITS sequencing have disease suppressive efects on FRCR in Canada; (A.C.G., S.A.B.) Department of Biology,
was that it could resolve to species Until barley University of Ottawa, 30 Marie Curie, Ottawa,
sequencing technologies can yield full length ON K1N 6N5, Canada.
ITS sequencing laborious traditional culturing 66. Impacts of ditch­buried garlic straw
followed by sequencing of the entire ITS fortified with chemical fertilizer on soil Soil­borne oomycete pathogens cause
region can give insights into microbiomes not microbial biomass, bacterial community devastating crop losses; thus it is critical to
revealed by current metagenomic methods and yield of a tunnel­grown chili find means of controlling them with standard
I O OLASUPO C HE Y LI AND X YU The agronomic practices Past research has re­
65. Cover crops differentially affect root Institute of Vegetables and Flowers, Chinese vealed little about how oomycete community
disease susceptibility by changing the soil Academy of Agricultural Sciences, Beijing structure changes in response to management
microbiome 100081, Peoples Republic of China. strategies such as tillage and crop­rotation
H AIYER R MATTERS C CALDWELL A MILLS Furthermore despite their economic impor­
A MCKENZIE­GOPSILL T FRASER AND A A study was conducted to investigate the tance as serious pathogens such as species
FOSTER (H.A., R.M., A.M., A.M.G., T.F., A.F.) impacts of bur ying garlic residue in ditches from genera Pythium and Phytophthora,
Charlottetown Research and Development fortifying same with diferent rates of chemical oomycete communities are still underrepre­
Centre, Agriculture and Agri-Food Canada, 440 fertiliZer on the soil microbial biomass and sented in large soil microbiome studies To
University Avenue, Charlottetown, PE C1A 4N6, rhiZospheric bacterial community diversity address these knowledge gaps 224 composite
Canada; and (H.A., C.C.) Dalhousie University - and structure and yield of a plastic­tunnel soil samples were collected from a split­plot
Agricultural Campus, PO Box 550, Truro, NS B2N grown chili The experimental treatments tillage and rotation experiment over a three­
5E3, Canada. comprised - residue with 25% recommended year period An amplicon sequencing strategy
chemical fertiliZer (R25) residue with 50% was employed to assess oomycete communi­
Barley and soybean two of the most im­ chemical fertiliZer (R50) sole residue (SR) ty changes To improve detection specificity
portant crops in PEI are both susceptible to 100% chemical fertiliZer (CF) and unfertiliZed novel oomycete­specific primers targeting two
root disease caused by Fusarium spp The control with no residue (C) Chili yield in CF DNA markers the internal transcribed spacer
influence of cover crops on the soil micro­ was 20 ­ 45% significantly higher than those 1 (ITS1) of ribosomal DNA and the ribosomal
biome and subsequent root disease of cash elicited by the other treatments The soil protein S10 gene (rps10) were used This led
crops caused by Fusarium spp is not clear microbial biomass carbon and nitrogen in us to develop a high­quality reference data­
Cover crop efects on the soil microbiome and fortified­residue and CF plots were higher than base (refDB) for the ITS1 region and to obtain
influence on subsequent crops' susceptibility in SR and the control even though they were a rps10 refDB from http //oomycetedb cgrb
to root disease was studied at the AAFC Har­ statistically similar Total carbon content in oregonstate edu/ While both markers had a
rington Research Farm PE from 2018 to 2020 R25 and R50 were higher than those from the good coverage of Pythium which was most
Year 1 field trials were planted in a split­plot CF SR and the control NH ­N was significant­ prevalent in soils the rps10 marker recov­
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design with 8 individual cover crops as well ly increased by R50 treatment while CF plot ered higher Phytophthora diversity as well as
as 3 cover crop mixtures and year 2 planted had the highest NO ­N followed by R50 Soil Aphanomyces which was not detected by the
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to barley or soybean seeded no­till Destruc­ microbial quotient and N­mineraliZation quo­ ITS1 marker Preliminar y analyses suggested
tively sampled barley and soybean were rated tient were not influenced by the treatments that no­till increased oomycete diversity while
for Fusarium root and crown rot (FRCR) The Results obtained from 16S rRNA high through­ rotation efects were more complex This study
efects of cover crop soil on FRCR of soybean put sequencing revealed that CF influenced will shine a light on how common agricultural
and barley were further analyZed in a green­ the diversity in the rhiZospheric microbiome practices could help in managing and mitigat­
house (GH) trial In the field high le vel of FRCR with a higher Chao 1 index and phylogenetic ing these important soil phytopathogens
was obser ved in both cash crops and cover diversity although the bacterial communi­
crops were found to significantly influence dis­ ty composition at both phylum and genus
ease Barley planted afer oilseed radish had levels were not enriched by the treatments

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