INCORPORATION OF THE SEQUENCE LISTING

The present application contains a sequence listing that was submitted herewith in ASCII format via EFS-Web, containing the file name 36446_0235U3_SL which is 47,733 bytes in size, created on Oct. 26, 2020, and is herein incorporated by reference in its entirety pursuant to 37 C.F.R. § 1.52(e)(5).

FIELD

The present disclosure relates to compositions and methods useful in enhancing pathogen resistance in legume plants, and more particularly in soybean plants, by providing to the plants a gene or gene(s) that are associated with resistance to the causal agent of Asian soybean rust (ASR). The disclosure further relates to polynucleotides capable of enhancing resistance in legumes to ASR and methods of using these polynucleotide sequences to make a transgenic legume plant that is resistant to ASR.

BACKGROUND

Soybeans (Glycine max), a major industrial use crop, are also one of the most important protein source crops, and are considered a key food group for preventing disease and optimizing health by many public health organizations including the American Diabetes Association, the American Heart Association and the American Cancer Society. Asian soybean rust (ASR) is a major crop disease affecting soybeans and can negatively affect growth and yield. It is caused by the obligate biotrophic fungusPhakopsora pachyrhiziand to a lesser extent, the closely related fungusPhakopsora meibomiae. The disease can cause yield losses ranging from 10-90%.

SUMMARY

The present disclosure relates to compositions and methods for identifying rust resistance genes from legume species and transforming those genes into legume crops or a legume crop species, such asGlycine max, to generate plants that are resistant to ASR.

Disclosed herein are isolated polynucleotides comprising a nucleotide sequence that encodes a legume-derived NB-LRR polypeptide having at least 90% amino acid sequence identity to a legume sequence disclosed herein. In an aspect, a plant transformed with the polynucleotide displays enhanced resistance to Asian soybean rust when compared to a susceptible plant and/or a non-transformed plant. Also disclosed are recombinant DNA constructs comprising the polynucleotides described herein.

Disclosed herein are useful polypeptides which can include, consist of, or be encoded by a polynucleotide or sequence of SEQ ID NO: 1-8, and variants thereof.

Disclosed herein are methods of conferring disease resistance in a legume crop species (e.g., soybean), the method comprising transforming a legume crop species with a heterologous legume-derived NB-LRR gene that confers disease resistance to a legume crop species disease (e.g., ASR).

Disclosed herein is a transgenic legume crop plant stably transformed with a recombinant DNA construct. In an aspect, the recombinant DNA construct comprises polynucleotides disclosed herein that encode one or more legume-derived NB-LRR resistance genes that are capable of conferring resistance to a plant disease, such as ASR. In an aspect, the polynucleotide comprises one or more non-legume-derived NB-LRR resistance genes and/or non-NB-LRR resistance genes that are capable of conferring resistance to a plant disease. The polynucleotides described herein can also comprise any combination of resistance genes. The transgenic legume crop plant can comprise one or more agronomic traits. Obtaining the seeds from such transgenic legume crop plants is also contemplated. Further, the present disclosure also features a transgenic legume crop plant that is stably transformed that comprises the legume-derived NB-LRR poly nucleotide that has at least 90% sequence identity to a sequence described herein.

Disclosed herein are methods of identifying one or more resistance genes conferring resistance to a plant disease (e.g., ASR).

Disclosed herein are methods of producing an ASR resistant plant (e.g., a legume species). In an aspect, the method comprises transforming a plant cell with a legume-derived NB-LRR resistance gene. The method can further comprise regenerating the transformed plant from the transformed plant cell. In an aspect, the method comprises growing the transformed plant such that the expression of the legume-derived NB-LRR resistance gene produces a transformed plant that displays enhanced resistance to ASR disease.

Disclosed herein are methods of producing a legume plant that is a progeny from a cross with a legume plant comprising a legume-derived NB-LRR resistance gene described herein.

Disclosed herein are methods of assaying a legume plant for disease resistance to a plant disease (e.g, ASR). In an aspect, the method comprises exposing a portion of the legume plant to a plant pathogen (e.g.,Phakopsora pachyrhizi); measuring plant disease symptoms on the legume plant exposed to the plant pathogen; and comparing the plant disease symptoms to a reference standard for disease resistance.

Disclosed herein are methods of enhancing plant resistance to ASR disease. In an aspect, the method comprises conferring resistance to an ASR pathogen (e.g.,Phakopsora pachyrhizi) by introgression of a legume-derived NB-LRR resistance gene into germplasm (e.g., a legume crop species) in a breeding program for resistance to ASR. The method features a legume-derived NB-LRR resistance gene that encodes an NB-LRR polypeptide. In an aspect, the NB-LRR polypeptide comprises an amino acid sequence having at least 90% homology to a legume-derived NB-LRR polypeptide disclosed herein. The method described herein also features a plant transformed with the polypeptide that displays enhanced resistance to ASR when compared to a susceptible plant.

