Organic compounds -- part of the class 532-570 series – Organic compounds – Carbohydrates or derivatives
Reexamination Certificate
1999-05-14
2002-11-05
Brusca, John S. (Department: 1631)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbohydrates or derivatives
C536S024300, C435S006120
Reexamination Certificate
active
06476212
ABSTRACT:
DESCRIPTION OF THE COMPACT DISK-RECORDABLE (CD-R)
CD-R 1 contains the Sequence Listing formatted in plain ASCII text. CD-R 1 is labeled with Identification No. PL-0017 US, 1 of 3, Copy 1. The file containing the Sequence Listing is entitled p10017.txt, created on Nov. 22, 2000, and is 3,929 KB in size.
CD-R 2 is an exact copy of CD-R 1. CD-R 2 is labeled with Identification No. PL-0017 US, 2 of 3, Copy 2.
CD-R 3 contains the Computer Readable Form of the Sequence Listing in compliance with 37 C.F.R. §1.821(e), and specified by 37 C.F.R. §1.824. CD-R 3 is labeled with Identification No. PL-0017 US, 3 of 3, Copy 3. The file containing the Sequence Listing is entitled pl0017.txt, created on Nov. 22, 2000, and is 3,929 KB in size.
The disclosure of the Sequence Listing submitted as an electronic document on compact disc as described above are to be part of the permanent USPTO record of this patent application and are hereby expressly incorporated by reference.
FIELD OF THE INVENTION
The present invention relates to nucleic and amino acid sequences derived from corn ear and to the use of these sequences in the identification, evaluation, and alteration of desired characteristics associated with growth and development, disease resistance, environmental adaptability, quality, and yield.
BACKGROUND OF THE INVENTION
The field of plant breeding deals with the manipulation of plant genomes with the purpose of improving characteristics of the plant. Plant breeders use data and methodology from plant physiology, genetics, biochemistry, pathology, statistics, and molecular biology. One of the most improved hybrid crops is corn,
Zea mays
(L.). Corn is presently the second-most economically important crop in the United States. Acreage of field corn (used for livestock feed, corn starch, corn syrup, fuel ethanol, and oil) and sweet corn (used fresh or processed for human consumption) exceeds that of any other agronomic crop. Annual losses, reduction in quality and yield, due to diseases and infestation may range from 7 to 17%. Studies of corn may be used as a model for other economically important agronomic grasses.
Corn is a monocotyledonous plant which has one seed leaf, uses the C
4
photosynthetic pathway, and has scattered vascular bundles. The mature plant is made up of roots, stem, leaves, and reproductive structures. The root system functions to anchor the plant and to absorb water and nutrients. The corn stem consists of a series of nodes, each bearing one bladelike leaf with parallel veins, and internodes, elongated stem sections. The stem and its leaves are commonly referred to as a stalk. Leaves arise alternately and are arranged in two rows along either side of the stem. The male reproductive structure is the tassel, and its flowers produce pollen. The female reproductive structure is the ear, and its flowers each have a silk for pollination. When a pollen grain is shed onto a silk and germinates, a pollen tube grows down the silk and delivers two sperm to the female gametophyte. Within the gametophyte, one sperm fertilizes the egg, and the other, two polar nuclei. The embryo and endosperm produced by this double fertilization develop into the seed which matures in about two months.
The vegetative (V) and reproductive (R) stages of growth for a corn plant are as follows: VE-emergence from the soil of the seedling leaf; V1-first true leaf; V2-second leaf; . . . V(n)-nth leaf; VT-tasseling stage; and reproductive stages, R1-silking; R2-blister; R3-milk; R4-dough; R5-dent; and R6-physiological maturity (Ritchie, S. W. et al. (1986)
How a Corn Plant Develops
, Iowa State University Cooperative Extension Service, Ames IA 48:1-21).
Corn Ear
Ear shoots are initiated at V3. As the primary apical meristem makes the transition from vegetative growth to tassel formation, the plant also begins to initiate buds in the axils of vegetative leaves. Ear primordia arise beginning at about the sixth node and proceed upward until about two nodes below the developing tassel. The earliest anatomical indications of ear development are periclinal divisions in the second and third cell layers of the shoot meristem followed by divisions in the outermost layer. This axillary floral meristem becomes organized and elongates to produce 8-14 husks which surround the developing cob. The husks remain shorter, and the sheaths become thinner and broader than those of ordinary leaves. Although the outer husks are arranged in two rows, the inner ones can be in several rows. During cob development, the floral meristem elongates and bifurcates one or more times; each bifurcation produces bracts in two ranks and eventually determines the number of rows of kernels on the cob. Each bract produces two spikelets, and each spikelet ultimately produces a single floret. Spikelet development parallels that of other graminaceous flowers and produces the following succession of flower parts (from the outside to inside): glumes, lemma, palea, stamen primordia which abort, and a terminal gynoecium. Gyonecial development begins with the enlargement of the ovary wall around the ovule followed by terminal elongation to form the silk (Sundberg, M. D., et al. (1995) Amer J Bot 82:64-74; Cheng, P. C., et al. (1983) Amer J Bot 70:450-462; and Johri, M. M. and Coe, Jr., E. H. (1983) Dev Biol 97:154-172).
Ear shoots are often visible at V6, and by V9, many ear shoots can be seen with appropriate dissection. An ear shoot may develop at every above-ground node with the exception of the last six to eight nodes below the tassel. Consistent with the age of each node and determined apical development, each ear develops faster than the ear originating above it on the stalk. However, growth of most lower ears eventually slows, and only the upper one or two ears ever mature and are harvested. At V12, the number of potential kernels on each ear and the size of the ear are determined. Although the number of rows of kernels per ear has already been established, cob elongation and the determination of the number of kernels per row will not be complete until about one week before silking, about V17.
By V15, upper ear development has surpassed that of lower ears, and silks are just beginning to grow from the ovules. Between V18 and R1, the silks grow acropetally from the basal ovules to those at the ear tip. R1 begins when any silks are visible outside the husks. Pollination occurs when wind borne pollen grains fall on these new, moist silks. Germination and growth of the pollen grain down the silk to the ovule where fertilization occurs takes about 24 hours. Generally two to three days are required for all silks on a single ear to be exposed and pollinated. The silks continue to elongate until they are fertilized or environmental or biological conditions cause their demise. The fertilized ovules immediately begin kernel development (Ritchie, S. W. et al. (1986)
How a Corn Plant Develops
, Iowa State University Cooperative Extension Service, Ames IA 48:1-21).
Problems of Corn Ears
All parts of the corn plant are susceptible to diseases, insect infestations, and stress. These conditions are usually diagnosed by their above-ground leaf, stalk, fruit and/or seed symptoms and are caused by fungi, bacteria, mycoplasmas and related organisms, viruses, nematodes, parasitic seed plants, insects and mites, and abnormal environmental conditions.
Fungal diseases are spread by spores that germinate under favorable conditions of temperature and moisture. Spores germinate to produce branched threads called hyphae that infect plants by direct penetration of the epidermis or through natural openings or wounds. Resting bodies (chlamydospores, sclerotia) allow fungi to survive under unfavorable conditions for long periods in the soil or in plant debris.
Head smut, caused by the fungus,
Sphacelotheca reiliana
, occurs in the deltas and mountain valleys of the Pacific Coast states, in the high plains of Texas, and in southeastern Europe. This soil-borne fungus appears in fields where nitrogen is deficient at the time of ear and tassel formation. Galls containing masses
Ito Laura Y.
Lalgudi Raghunath V.
Sherman Bradley K.
Brusca John S.
Incyte Genomics Inc.
Incyte Genomics, Inc.
Moran Marjorie A.
Murry Lynn E.
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