Abscisic acid induction of cloned cotton late embryogenesis-abundant (Lea) mRNAs

Abstract

Earlier studies found that cotton (Gossypium hirsutum L.) cotyledons contain several mRNAs which are more abundant during late embryogenesis than in mid-embryogenesis or early germination. They are here termed 'Late embryogenesis-abundant' mRNAs, encoded by Lea loci. Complementary DNA clones for 18 such mRNA sequences, defined at a hybridization criterion of Tm-15°C, were identified in a mature embryo cDNA library by differential cDNA hybridization. At a lower hybridization criterion, some sequence homology was found within several of these cloned Lea mRNA sequences. Each Lea mRNA sequence comprises 0.04-1.3% of mature embryo poly(A)(+) mRNA, a level ten-fold to several hundred-fold higher than in young embryo or 24 h seedling poly(A)(+) mRNA. Of 18 Lea mRNA sequences examined in cultured young embryos, the level of at least 13 are specifically increased by exogenous abscisic acid (ABA), several to a level near that in normal mature embryos. However, the abundance of several of the sequences does not appear to be significantly modulated by ABA. The LEA polypeptides encoded by 10 Lea mRNA sequences were identified by hybrid-arrested translation. They include most of the late embryogenesis-abundant, ABA-inducible, polypeptides previously identified. Preliminary results suggest that many of the individual Lea mRNA sequences are transcribed from 1-3 genes in each of cotton's two subgenomes.

Seed 1-Cysteine Peroxiredoxin Antioxidants Are Not Involved in Dormancy, But Contribute to Inhibition of Germination during Stress

“…Total RNA was precipitated in one-third volume of 8 m LiCl on ice for 14 to 20 h. After centrifugation (9,000 rpm, 30 min, and 4°C), the RNA pellet was resuspended in 100 L of Tris-EDTA solution (10 mm Tris-HCl, pH 8.0, and 1 mm EDTA, pH 8.0), precipitated in 150 L of 5 m KAc, pH 6.5, for 3 to 5 h on ice, and centrifuged as above, followed by a final ethanol precipitation. For northern analyses 0.5 g of mRNA or 10 g of total RNA was separated on a denaturing RNA gel, blotted, and hybridized as described (Galau et al, 1986).…”

A repeating 11‐mer amino acid motif and plant desiccation

“…(Galau et a/., 1986). Each type of Lea protein was found to emanate from a small rnultigene family-of two to four members.…”

Cellular Concentrations and Uniformity of Cell-Type Accumulation of Two Lea Proteins in Cotton Embryos.

“…They were given the mnemonic designation Lea (late embryogenesis abundant) to indicate their developmental period of abundance. By 1986 it was recognized that their accumulation was reflected in the levels of their mRNAs, suggesting that their appearance and accumulation was largely transcriptionally regulated (Galau et al, 1986). Further, it was noted that these proteins and their mRNAs could be induced to accumulate earlier in embryogenesis in excised embryos incubated in exogenous abscisic acid (ABA) (Galau et al, 1986).…”

“…By 1986 it was recognized that their accumulation was reflected in the levels of their mRNAs, suggesting that their appearance and accumulation was largely transcriptionally regulated (Galau et al, 1986). Further, it was noted that these proteins and their mRNAs could be induced to accumulate earlier in embryogenesis in excised embryos incubated in exogenous abscisic acid (ABA) (Galau et al, 1986). Representatives of six different lea gene families were sequenced by 1988 (Baker et al, 1988).…”

“…The proteins chosen are members of the D-7 and D-113 families from cotton embryos (Galau et al, 1986). Analyses of the amino acid sequences of the Lea families indicate two principal structural groups of proteins as predicted by the computer algorithms of Chou and Fasman (1978), Granier et al (1978), and Argos (1989).…”