The allocation of carbon and nitrogen resources to the synthesis of plant proteins, carbohydrates, and lipids is complex and under the control of many genes; much remains to be understood about this process. QQS (Qua-Quine Starch; At3g30720), an orphan gene unique to Arabidopsis thaliana, regulates metabolic processes affecting carbon and nitrogen partitioning among proteins and carbohydrates, modulating leaf and seed composition in Arabidopsis and soybean. Here the universality of QQS function in modulating carbon and nitrogen allocation is exemplified by a series of transgenic experiments. We show that ectopic expression of QQS increases soybean protein independent of the genetic background and original protein content of the cultivar. Furthermore, transgenic QQS expression increases the protein content of maize, a C4 species (a species that uses 4-carbon photosynthesis), and rice, a proteinpoor agronomic crop, both highly divergent from Arabidopsis. We determine that QQS protein binds to the transcriptional regulator AtNF-YC4 (Arabidopsis nuclear factor Y, subunit C4). Overexpression of AtNF-YC4 in Arabidopsis mimics the QQS-overexpression phenotype, increasing protein and decreasing starch levels. NF-YC, a component of the NF-Y complex, is conserved across eukaryotes. The NF-YC4 homologs of soybean, rice, and maize also bind to QQS, which provides an explanation of how QQS can act in species where it does not occur endogenously. These findings are, to our knowledge, the first insight into the mechanism of action of QQS in modulating carbon and nitrogen allocation across species. They have major implications for the emergence and function of orphan genes, and identify a nontransgenic strategy for modulating protein levels in crop species, a trait of great agronomic significance.QQS | NF-YC4 | carbon allocation | nitrogen allocation | orphan C arbon and nitrogen allocation to plant proteins, carbohydrates, and lipids is not controlled by a single gene but by many (1). Most of the enzymes promoting accumulation of these products have been identified; however, much less is understood about the mechanisms that regulate this complex metabolic network (2-8).Arabidopsis thaliana QQS (Qua-Quine Starch; At3g30720) lacks sequence similarity to any other protein-coding genes, and is considered an orphan gene that has arisen de novo from noncoding sequence since the divergence of A. thaliana from other species (9, 10). Although orphans typically comprise 2-8% of the genome of eukaryotic and prokaryotic species, their origin and biological function have not been well-explored (11)(12)(13)(14). Proteins encoded by some orphan genes provide a defensive capability by binding to a receptor of a predator organism (11). In contrast, QQS action is endogenous (3): Overexpression of QQS in Arabidopsis increases total protein content and decreases total starch content in leaf, whereas down-regulation of QQS has the converse effect. The increased starch content in QQS RNAi (RNA interference) mutants is due to increased starch accumu...

The maize (Zea mays) shoot apical meristem (SAM) arises early in embryogenesis and functions during stem cell maintenance and organogenesis to generate all the aboveground organs of the plant. Despite its integral role in maize shoot development, little is known about the molecular mechanisms of SAM initiation. Laser microdissection of apical domains from developing maize embryos and seedlings was combined with RNA sequencing for transcriptomic analyses of SAM ontogeny. Molecular markers of key events during maize embryogenesis are described, and comprehensive transcriptional data from six stages in maize shoot development are generated. Transcriptomic profiling before and after SAM initiation indicates that organogenesis precedes stem cell maintenance in maize; analyses of the first three lateral organs elaborated from maize embryos provides insight into their homology and to the identity of the single maize cotyledon. Compared with the newly initiated SAM, the mature SAM is enriched for transcripts that function in transcriptional regulation, hormonal signaling, and transport. Comparisons of shoot meristems initiating juvenile leaves, adult leaves, and husk leaves illustrate differences in phase-specific (juvenile versus adult) and meristem-specific (SAM versus lateral meristem) transcript accumulation during maize shoot development. This study provides insight into the molecular genetics of SAM initiation and function in maize.

Enhancing the nutritional quality and disease resistance of crops without sacrificing productivity is a key issue for developing varieties that are valuable to farmers and for simultaneously improving food security and sustainability. Expression of the Arabidopsis thaliana species-specific AtQQS (Qua-Quine Starch) orphan gene or its interactor, NF-YC4 (Nuclear Factor Y, subunit C4), has been shown to increase levels of leaf/seed protein without affecting the growth and yield of agronomic species. Here, we demonstrate that overexpression of AtQQS and NF-YC4 in Arabidopsis and soybean enhances resistance/reduces susceptibility to viruses, bacteria, fungi, aphids and soybean cyst nematodes. A series of Arabidopsis mutants in starch metabolism were used to explore the relationships between QQS expression, carbon and nitrogen partitioning, and defense. The enhanced basal defenses mediated by QQS were independent of changes in protein/carbohydrate composition of the plants. We demonstrate that either AtQQS or NF-YC4 overexpression in Arabidopsis and in soybean reduces susceptibility of these plants to pathogens/pests. Transgenic soybean lines overexpressing NF-YC4 produce seeds with increased protein while maintaining healthy growth. Pull-down studies reveal that QQS interacts with human NF-YC, as well as with Arabidopsis NF-YC4, and indicate two QQS binding sites near the NF-YC-histone-binding domain. A new model for QQS interaction with NF-YC is speculated. Our findings illustrate the potential of QQS and NF-YC4 to increase protein and improve defensive traits in crops, overcoming the normal growth-defense trade-offs.

To improve the nitrogen use efficiency (NUE) of crops to increase yields, one approach is to develop crops with improved NUE. Qua Quine Starch (QQS), a species-specific orphan gene present only in Arabidopsis thaliana, has a novel, unexpected functionality. Approximately 0.5-8% of genes in a given species are uniquely present in that species, having no homologs in other species. They represent a significant fraction of eukaryotic and prokaryotic genomes, and are thought to be a determinant of the character of a species. However, little is known about the functional significance of these so-called species-specific or orphan genes. QQS can affect the extremely important trait of protein content when expressed in other species, in soybean, maize and rice. Understanding QQS functions has multiple impacts, revealing how plants partition precious carbon and nitrogen resources. Here, we report QQS interactor nuclear factor Y subunit C4 (NF-YC4), affects carbon and nitrogen allocation to protein in soybean and maize. QQS and its related network may be used as a tool to increase the protein content in crops, and to study the 2 nitrogen allocation network. RNA-Sequencing analyses of the QQS mutant materials have identified candidate genes involved in regulation of nitrogen allocation. Abstract 19To improve the nitrogen use efficiency (NUE) of crops to increase yields, one approach is to 20 develop crops with improved NUE. Qua Quine Starch (QQS), a species-specific orphan gene 21 present only in Arabidopsis thaliana, has a novel, unexpected functionality. Approximately 0.5-22 nitrogen allocation network. RNA-Sequencing analyses of the QQS mutant materials have 32 identified candidate genes involved in regulation of nitrogen allocation. 33 34

We consider the problem of testing each of m null hypotheses with a sequential permutation procedure in which the number of draws from the permutation distribution of each test statistic is a random variable. Each sequential permutation p-value has a null distribution that is nonuniform on a discrete support. We show how to use a collection of such p-values to estimate the number of true null hypotheses m0 among the m null hypotheses tested and how to estimate the false discovery rate (FDR) associated with p-value significance thresholds. We use real data analyses and simulation studies to evaluate and illustrate the performance of our proposed approach relative to standard, more computationally intensive strategies. We find that our sequential approach produces similar results with far less computational expense in a variety of scenarios.