MicroRNA polymorphisms conferring enhanced drought tolerance in a plant

#The field of the invention relates generally to plants with desirable phenotypic characteristics. The invention relates to identifying plant single nucleotide polymorphisms (SNPs) within microRNA regions that confer desirable agronomic phenotypes. The invention also relates to introgressing desirable agronomic phenotypes into plants by selecting plants comprising for one or more SNPs and breeding with such plants to confer such desirable agronomic phenotypes to plant progeny.

#A goal of plant breeding is to combine, in a single plant, various desirable traits. For field crops such as corn, these traits can include greater yield and better agronomic quality. However, genetic loci that influence yield and agronomic quality are not always known, and even if known, their contributions to such traits are frequently unclear. Thus, new loci that can positively influence such desirable traits need to be identified and/or the abilities of known loci to do so need to be discovered.

#Previous studies have focused primarily on the identification and manipulation of candidate genes that encode proteins, such as transcription factors. These genes could encode proteins that directly affect the physiology of the plant or transcription factors that regulate these effector genes.

#These and other features, aspects, and advantages of the present invention are better understood when the following Detailed Description is read with reference to the accompanying figures.

#FIGS. 1A-1P. Alignment of miRNA 169g sequence to identify SNPs. The 169g mature miRNA and pre-miRNA are indicated by the identifiers mature_miRNA1123 (SEQ ID NO:43) and pre_miRNA/1141 (SEQ ID NO:44), respectively. The wild type B73 sequence is indicated by the identifier, PUGHP42.R (SEQ ID NO:45). The miR169g locus has been mapped to the survey sequence, PUGHP42.R. The other corn lines aligned are: ID7002./1775 (SEQ ID NO:46); AA3941./1769 (SEQ ID NO:47); AF4031./1743 (SEQ ID NO:48); AX5707./1782 (SEQ ID NO:49); BB3004./1775 (SEQ ID NO:60); CC8032./1763 (SEQ ID NO:51); CE8415./1747 (SEQ ID NO:52); FSNU505./1735 (SEQ ID NO:53); HT7049HL./1754 (SEQ ID NO:54); ID2618./1738 (SEQ ID NO:55); ID5829./1759 (SEQ ID NO:56); IJ6208./1719 (SEQ ID NO:57); IQ1332./1775 (SEQ ID NO:58); WR0588./1759 (SEQ ID NO:59); XF7110./1788 (SEQ ID NO:60); X05744./1759 (SEQ ID NO:61); XPFF003./1771 (SEQ ID NO:62); XPCC003./1731 (SEQ ID NO:63); PJ7065./1732 (SEQ ID NO:64); FF6096./1784 (SEQ ID NO:65); and CC7752./1770 (SEQ ID NO:66).

#FIGS. 2A-2L. Alignment of miRNA 171a sequences to identify SNPs. The 171a mature miRNA and pre-miRNA are indicated by the identifiers mature_miR171a (SEQ ID NO:67) and zma-MIR171a (SEQ ID NO:68), respectively. The wild type B73 sequence is indicated by the identifier, chr4_240118217 . . . 240118861 (SEQ ID NO:69). The other corn lines aligned are: IJ6208./1643 (SEQ ID NO:70); A01008./1626 (SEQ ID NO:71); BB3004./1644 (SEQ ID NO:72); CE8415./1573 (SEQ ID NO:73); DC4015./1587 (SEQ ID NO:74); FF6096./2619 (SEQ ID NO:75); PJ7065./1595. (SEQ ID NO:76); WR0588./1570 (SEQ ID NO:77); XF7110./1464 (SEQ ID NO:78); XO5744./1604 (SEQ ID NO:79); XPCC003./1613 (SEQ ID NO:80); and XPFF003./1622 (SEQ ID NO:81).

#Maize drought is one of the major limitations to maize production worldwide. When drought stress occurs just before or during the flowering period, an increase in the length of the anthesis-silking interval and a decrease in grain yield can result. Approximately 15% of the world's maize crop, or in excess of 19 million tons, is lost every year to drought. Identifying candidate genes that can enhance drought-stress tolerance in maize could lead to more efficient crop production in affected areas.

#What are needed, then, are new methods and compositions for genetically analyzing Zea mays varieties with respect to drought tolerance and for employing the information obtained for producing new Zea mays plants that have improved water optimization traits.

#Increased crop yield is a trait of considerable economic interest throughout the world. Yield is normally defined as the measurable produce of economic value from a crop. This may be defined in terms of quantity and/or quality. Yield is directly dependent on several factors, for example, the number and size of the organs, plant architecture (for example, the number of branches), seed production, leaf senescence and more. Root development, nutrient uptake, stress tolerance and early vigor may also be important factors in determining yield. In addition, it is greatly desirable in agriculture to develop crops that may show increased yield in optimal growth conditions as well as in non-optimal growth conditions (e.g. drought, under abiotic stress conditions). Optimizing the abovementioned factors may therefore contribute to increasing crop yield. In one aspect of the invention, maize plant comprising the nucleotide sequence as described herein may confer increased yield under optimal as well as in non-optimal conditions (e.g. drought or decreased water availability) as compared to a control plant.