Why some probes have "NA" for SYMBOL but having ENTREZID as well as the TAIR accession number and what can I do when single probe having more than one GENE SYMBOL, ENTREZID and TAIR Accession. Kindly suggest on below table. Which gene from the probe id 263153_s_at, I can select for further studies? Any suggestions would be highly appreciated.
Did you look at NCBI for information about that Entrez Gene ID? How about arabidopsis.org for the TAIR ID? If you had done so you would see that this is a hypothetical transcript with unknown function, in which case there isn't a gene symbol - NCBI just uses the TAIR ID.
Do note that we are just passing on existing information that we get from the manufacturer and either NCBI or EBI or TAIR (in this case). In almost all instances the reason something is missing has nothing to do with Bioconductor, but instead simply reflects what information is available to us. Your first recourse should be to check the data at the various online sources (including netaffx.com) to see if what we supply matches up with what's available.