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ARS Home » Southeast Area » Stoneville, Mississippi » Crop Genetics Research » Research » Publications at this Location » Publication #298400
Title: Microscopic Methods to Evaluate Gland Initiation and Development in Cotton Ovules

Author
item Scheffler, Jodi
item Taliercio, Earl
item Tonos, Jennifer
item Romano, Gabriela

Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2014
Publication Date: 12/21/2014
Citation: Scheffler, J.A., Taliercio, E.W., Tonos, J.L., Romano, G.B. 2014. Microscopic Methods to Evaluate Gland Initiation and Development in Cotton Ovules. Journal of Cotton Science. 18:420-429.

Interpretive Summary: Gossypol is a compound found in cotton (Gossypium hirsutum L.) glands that helps protect the seed from pests and pathogens. Cotton seed use is mainly limited to cattle feed, because gossypol is toxic to most animals, except ruminants. Lowering the gossypol content in the seed would increase the possible uses for cotton seed. Developing new strategies to modify gossypol in cotton seed requires a better understanding of the developmental timing of gossypol containing glands. The first step is to determine when gossypol glands are initiated and filled with gossypol. Gland development was investigated using digital microscopy that allows the developing seed to be quickly observed and saved as a two dimensional full color image at high magnification. Images were made over several weeks and showed the seed with no glands formed through fully developed glands filled with gossypol. New high throughput sequencing and gene expression studies often require accurate identification of developmental stage or tissue condition. The digital microscopy methods established to determine the pattern of cotton gland formation and timing of gossypol filling the glands, are simple methods that can be also used for other plant species. Knowing when gossypol appears in the glands allows precise sampling of developing seed for use in sequencing and gene expression studies to determine which genes could be modified to decrease gossypol production in the seed.

Technical Abstract: Gossypol is a terpenoid aldehyde found in cotton (Gossypium hirsutum L.) glands that helps protect the seed from pests and pathogens. Cotton seed use is mainly limited to cattle feed, because gossypol is toxic to most animals, except ruminants. Lowering the gossypol content in the seed would increase the possible uses for cotton seed. Developing new strategies to modify gossypol in cotton seed requires a better understanding of the development of gossypol containing glands. The first step is to determine when gossypol glands are initiated and filled with gossypol. Gland development was investigated using microscopic images of developing seeds from ten glanded and two glandless cotton lines. A digital microscope with a VH-Z20R (20X to 200X) lens was used to capture developing ovule (seed) images at 14 to 22 days after flowering (DAF). One boll per plot was imaged for each DAF time point and five different sets of time intervals were collected in each of two years. Imaging revealed empty glands forming as early as 14 DAF and as late as 20 DAF. For most of the entries, some glands were filling by 18 DAF and as early as 16 DAF for ultra early lines (< 110 days to maturity).