Nature and Patterns of Proteins during Cotton Seed Development

Abstract

Patterns of accumulation and ontogenetic relationships among proteins of cotton (Gossypium hirsutum L.) seeds were examined between 10 days postanthesis and maturity (56 days). Total and extractable nitrogen contents were determined; alkali-and water-soluble proteins were assayed quantitatively and electrophoretically. Two alkali-soluble proteins present in the electrophoretogram of mature embryos first appeared at 21 days postanthesis; most of the final profile was established by 28 days. Except for minor changes centering around the 7th week of development, the pattern from 28 days to maturity was marked by intensification of bands. The quantity of water-soluble nitrogen increased through the first 21 days of development, then declined until 42 days, when it again began to increase; it reached its highest level at maturity. There was evidence of a high peptide content 7 weeks postanthesis.Although seed development in cotton (Gossypium hirsutum L.) has been described in several reports (5,6,16,18), studies of the pattern of protein accumulation during cotton seed development are lacking. Analyses of dry matter and mineral accumulation and distribution within the developing cotton fruit indicated that the carpel walls contribute a significant proportion of their nitrogen to developing seed (16, 18). Significant incorporation of photosynthetically assimilated '4C has been measured throughout seed development (2).During the first few weeks of cotton seed development, nearly half of the seed nitrogen is found in the nonprotein pool (6). Although the amino acids in this nonprotein nitrogen pool show little similarity to the amino acid profile of mature cotton seeds, they probably reflect the composition of the amino acids supplied to the developing seeds. Not until midway in seed development does the amino acid composition of the cotton seed begin to resemble the mature seed profile (6). Studies of seed protein development have commonly measured crude protein accumulation and/or dynamic aspects of amino acid composition (6,14,20) (1 1, 12). Differential solubility of proteins can also be employed to separate seed proteins into classes, the development of which can be further investigated with other techniques (3). Temporal differences in accumulation rates and quantities of various protein fractions appear to be common, as do generic differences for seed proteins.We have applied these procedures to an investigation of seed protein accumulation in cotton, a species that has potential as a source of food protein and has previouslv been used in studies of developmental biochemistry (13). We report here the accumulation of and developmental changes in alkali-and water-soluble proteins as revealed by changes in electrophoretic patterns during the period of seed formation. MATERIALS AND METHODSFlowers of cotton (G. hirsutum L. cv. Stoneville 7A glandless) were tagged at anthesis in field plots at Stoneville on July 27, 1977. Tagged bolls (fruit) were harvested first at 10 days postanthesis, and then weekly between...

Measuring the maturity of unopened cotton bolls with near infrared spectroscopy

“…13 displayed photographs of whole cottonseeds and it was evident that the seed coat had changed from white in color at 40 DPA to a distinct dark color by 45 DPA, and this coincides with the changes in starch reported by Hendrix 15 and the information about water content reported by Liu et al. 14 For protein, King and Leffler 16 showed that cottonseed derived water soluble proteins increased steadily during the final stages of seed maturation, while alkali soluble storage proteins increased rapidly from approximately 21 DPA and had stabilized by around 50 DPA. Elmore and Leffler 17 reported that cottonseed protein N levels gradually increased throughout boll development.…”

Qualitative and quantitative changes in nitrogenous compounds in senescing leaf and bark tissues of the apple

“…1978, Sun etal. 1978, Most of the final protein profile of cotton seeds was established by 28 days post-anthesis in the 56-day-period from post-anthesis to maturity (King and Leffler 1979), At least 15 different protein species could be distinguished from the scanning profiles at the dormant stage of apple shoot bark (Figure 3). O'Kennedy and Titus (1979) found at least 12 different protein species in rooted cuttings of MM 106.…”

A Review of Cottonseed Protein Chemistry and Non-Food Applications

“…From SDS-PAGE analysis, cottonseed protein was separated into several distinct protein components with different molecular weights [48]. The molecular weight changes with maturation [49]. Recently, Singh et al [50] applied one-and two-dimensional gel electrophoresis to explore the cottonseed protein characteristics.…”