my %dict =  map { chomp; split "\t", $_, 2 } <$fh>;

##</code><code>##

 > grpsTbl <- read.csv("Orthogroups_3.csv", header=T, sep = "\t", row.names = 1, stringsAsFactors=F)

##</code><code>##

"PBANKA_0000600, PBANKA_0000701, PBANKA_0000801, PBANKA_0001001, PBANKA_0001101, PBANKA_0001201, PBANKA_0001301, PBANKA_0001401, PBANKA_0001501, PBANKA_0006300, PBANKA_0006401, PBANKA_0006501, PBANKA_0006600, PBANKA_0006701,"

##</code><code>##

"PmUG01_00010100.1-p1, PmUG01_00010200.1-p1, PmUG01_00010400.1-p1, PmUG01_00010500.1-p1, PmUG01_00010600.1-p1, PmUG01_00010700.1-p1, PmUG01_00010800.1-p1, PmUG01_00010900.1-p1, PmUG01_00011000.1-p1, PmUG01_00011300.1-p1, PmUG01_00011400.1-p1, PmUG01_00011600.1-p1, PmUG01_00011700.1-p1, PmUG01_00012100.1-p1, PmUG01_00012200.1-p1,"

##</code><code>##

PVX_088085	Protein processing in endoplasmic reticulum	
PVX_114095	Protein processing in endoplasmic reticulum	
PVX_123055	Ribosome biogenesis in eukaryotes
PYYM_1032000	-	
PYYM_1120600	-
PCYB_031930	Purine metabolism; Metabolic pathways; DNA replication; Pyrimidine metabolism

##</code><code>##

for my $k (keys %dict) {
  my $v=$dict{$k}; 
  warn 'for lookup:'.$k.' tab in field:'.$v."\n" if ($v=~"\t"); 
  }

##</code><code>##

for lookup:PVX_114095 tab in field:Protein processing in endoplasmic reticulum
for lookup:PYYM_1032000 tab in field:-
for lookup:PVX_088085 tab in field:Protein processing in endoplasmic reticulum

##</code><code>##

 
# This script was excerpted from http://stackoverflow.com/questions/11678939/replace-text-based-on-a-dictionary
use strict;
use warnings;
#use Text::CSV;
use Data::Dumper; 
  local $Data::Dumper::Deepcopy=1;
  local $Data::Dumper::Purity=1;
  local $Data::Dumper::Sortkeys=0;
  local $Data::Dumper::Indent=3; 

open my $fh, '<', 'kegg_pathway_title.txt' or die $!;
my %dict =  map { chomp; split "\t", $_, 2 } <$fh>;
warn Dumper \%dict; 
for my $k (keys %dict) {
  my $v=$dict{$k}; 
  warn 'for lookup:'.$k.' tab in field:'.$v."\n" if ($v=~"\t"); 
  }
#my %dict =  map { chomp; split ' ', $_, 2 } <$fh>;
my $re = join '|', keys %dict;
#close $fh;
open $fh, '<', 'Orthogroups_3.csv' or die $!;

while (<$fh>) {
print $. ."\n";
  next if $. < 2;
  my @a0=split("\t",$_); warn Dumper \@a0; 
  s/($re)/$dict{$1}/g;
  print;
}