Hello everyone (first post ever for me)

I am using Biomart in R and I am trying to obtain the maize homologs of a set of barley genes (I am only displaying one here for example's sake). Everything works fine when I use the getBM function for getLDS does not seem to work.

```r
host="plants.ensembl.org"
mysets<-listDatasets(useMart("plants_mart", host = host))
barley <- useDataset("hvulgare_eg_gene", mart = useMart("plants_mart", host = host))
zea <-useDataset("zmays_eg_gene", mart = useMart("plants_mart", host = host))
getLDS(attributes = c("ensembl_gene_id","description", "go_id","name_1006"),
   filters = "ensembl_gene_id", values = "HORVU.MOREX.r3.1HG0000220",
   mart = barley ,
   attributesL = c("ensembl_gene_id","description", "go_id","name_1006"), 
   martL = zea)
```

I get the following error message. I think the issue may be that the Virtual Schema is set to default, but I can't find how to change it to plants_mart

```r
Error in getLDS(attributes = c("ensembl_gene_id", "description", "go_id", : Query ERROR: caught BioMart::Exception::Usage: WITHIN Virtual Schema : default, Dataset hvulgare_eg_gene NOT FOUND
Traceback:

1. getLDS(attributes = c("ensembl_gene_id", "description", "go_id", 
 .     "name_1006"), filters = "ensembl_gene_id", values = "HORVU.MOREX.r3.1HG0000220", 
 .     mart = barley, attributesL = c("ensembl_gene_id", "description", 
 .         "go_id", "name_1006"), martL = zea)
2. stop(postRes)
```

Any help would be greatly appreciated
Great spot that this was related to the `virtualSchemaName`.  That was hardcoded to be `"default"` in **biomaRt** and no one has ever reported a problem before.  I assumed there were no Mart instances that ever used anything different!

Anyway, it's been patched in **biomaRt** version 2.50.3, which should be available from Bioconductor in the next few days.  If you want to get a copy before then you can install from Github with `BiocManager::install('grimbough/biomaRt', ref = 'RELEASE_3_14')`.

Here's an example with it working for a similar query:

```r
library(biomaRt)
packageVersion("biomaRt")
#> [1] '2.50.3'

ensembl_plants <- useEnsemblGenomes(biomart = "plants_mart")

barley <- useDataset("hvulgare_eg_gene", mart = ensembl_plants)
zea    <- useDataset("zmays_eg_gene", mart = ensembl_plants)

barley_gene_id <- "HORVU.MOREX.r3.4HG0381830"

getLDS(filters = "ensembl_gene_id", 
       values = barley_gene_id, 
       attributes = c("ensembl_gene_id","description", "go_id","name_1006"),
       mart = barley ,
       attributesL = c("ensembl_gene_id","description", "go_id","name_1006"), 
       martL = zea)

#>              Gene.stable.ID Gene.description GO.term.accession
#> 1 HORVU.MOREX.r3.4HG0381830               NA        GO:0016788
#> 2 HORVU.MOREX.r3.4HG0381830               NA        GO:0016788
#>                                GO.term.name Gene.stable.ID.1 Gene.description.1
#> 1 hydrolase activity, acting on ester bonds  Zm00001eb395980     Zm00001e038320
#> 2 hydrolase activity, acting on ester bonds  Zm00001eb395980     Zm00001e038320
#>   GO.term.accession.1                            GO.term.name.1
#> 1          GO:0016788 hydrolase activity, acting on ester bonds
#> 2          GO:0016787                        hydrolase activity
```