Expression of the Symbiotic nod4 Pea Gene against Various Genotypic Backgrounds

Abstract

Experiments on the effect of genotypic environment on the expression of the nod4 gene, responsible for supernodulation in pea, were performed. The genotypic background was found to affect the manifestation of both major symbiosis-related traits (number of nitrogen-fixing bacterial nodules and nitrogenase activity) and productivity-related traits (stem height, seed number, and seed weight), which form the pleiotropic complex of the mutant gene. Using recurrent selection, we developed supernodulating lines significantly exceeding the original mutant line and studied them up to generations F 5 -F 6 . Of special importance is the fact that these lines showed high levels of nodulation and nitrogen fixation. The results are discussed from the viewpoint of breeding. PLANT GENETICS

Never too many? How legumes control nodule numbers

“…Hence, the same receptor complex might control AON and SAM homeostasis, but the contributions of each receptor might vary in different plants to induce distinct effects. The nodulation4 (nod4) mutant also exhibits shoot-dependent hypernodulation, as well as nonsymbiotic phenotypes (Table 1) (Duc & Messager 1989;Sagan & Duc 1996;Sidorova & Shumnyi 2003;Sidorova et al 2005), but the affected gene is currently unidentified. In addition, in M. truncatula, a supernodulator mutant has been characterized, like sunn supernodulator (lss), with a phenotype similar to that of sunn mutants.…”

Plant Breeding for Biological Nitrogen Fixation: A Review

“…Generally, an overabundance of nodules has a deleterious effect on plant competitiveness as the increased nodulation demands an excessive carbohydrate supply (Voison et al, 2007). Sidorova et al (2005) found the nod4 SN inducing gene in field pea (Pisum sativum) to drastically limit plant growth and productivity while also reducing N fixation efficiency despite the large increase in nodulation. Attempting to remedy this effect, the SN mutant was crossed with three conventional cultivars (Torsdag, Truzhenik, and Falensky), and progeny were recurrently selected to the F 6 generation.…”

“…Nevertheless, all of the cultivar-mutant crosses incurred yield loss and growth reduction to some extent with the introduction of nod4 when compared to the conventional parent. Despite this result, a strong cultivar effect was observed on plant yield and growth, leading to the conclusion that N fixation and photosynthetic ability of the background genotype is a critical consideration when incorporating SN mutations in a breeding program and appropriate genetic background could ultimately justify wider use of SN in breeding programs (Sidorova et al, 2005).…”

Pleiotropy of pea RisfixC supernodulation mutation is symbiosis-independent

“…The supernodulating mutants blocked at the downstream stage of signalling like the shoot-determined pea mutants in loci SYM28 and SYM29 (Duc and Messager 1989;Sagan and Duc 1996;Voisin et al 2007), nod4 (Sidorova et al 2005) and nod6 (Nazaryuk et al 2006) have also been reported to be growth-depressed. However, like in the nod3 lines, the data are related to symbiotic plants, thus primarily pleiotropic and symbiosis-dependent components were not discriminated.…”

“…Growth depression is a common problem in overnodulated plants (Takahashi et al 2003;Sidorova et al 2005). The nodulation-induced changes are reparable by optimizing the nodule number to the physiologically tolerated level or by an increase in the photosynthetic capacity of the shoot.…”