Functional genetics of Lygus lineolaris
L. Margaret Allen
Biological Control of Pests Research Unit, United States
Department of Agriculture, Agricultural Research Service, Stoneville, MS, USA
Correspondence: meg.allen@ars.usda.gov
Functional genetics implies a robust understanding of the characteristics of a gene,
including where, when, and how it behaves in an organism. This level of
investigation has been mostly limited to model organisms such as yeast or
Drosophila. However, current technology and bioinformatics
allow for studies on non-model organisms such as the tarnished plant bug,
Lygus lineolaris. As a first step in identifying functional
genes, a cDNA library was prepared from a laboratory-reared colony of L.
lineolaris male nymphs. A small number of sequences were obtained and
compared to known genes. Sequences that appeared to have known functions or close
homologues have been targeted for further study. Three sequences appeared to encode
polygalacturonase (PG) enzymes, and cDNAs were cloned in their entirety by Rapid
Amplification of cDNA Ends (RACE). Other sequences of interest include actins,
tubulins, ribosomal subunits, proteinases, and cuticle genes. To identify expression
profiles for these genes, as related to developmental stage and sex of the insect,
total RNA samples were collected from eggs at 3 and 8 days of development, 2nd
instar nymphs, 5th instar nymphs (identifiable as either male or female) and adults,
male and female. Equal quantities of total RNA were reverse transcribed and used for
semiquantitative PCR. Several genes, including the PGs, were expressed with stage-
and sex-specificity. Constitutively expressed genes were identified and will be
useful as standards.
