Co-regulation of biomass partitioning by leafblade morphology genes AFILA, MULTIFOLIATE-PINNA, TENDRIL-LESS and UNIFOLIATA in grain pea Pisum sativum

Abstract

In grain pea Pisum sativum, 16 genotypes constructed by combining wild type and mutant alleles of MULTIFOLIATE- PINNA (MFP), AFILA (AF), TENDRIL-LESS (TL) and UNIFOLIATA (UNI) genes, which differed in leaf blade morphology, were quantitatively phenotyped for allometry. The biomass partitioning among root, stem, stipule, leaf blade and seeds was unique for these genotypes suggesting that MFP, AF, TL and UNI genes determined leaf blade and plant architecture. Gene actions were inferred on the basis of mutant phenotypes. Biomass of all the organs was found to be increased in the tl single mutant. The af mutation singly and in combination with mfp, mfp tl, mfp uni-tac or mfp tl uni-tac decreased biomass of all the organs. Allocation of biomass to leaves was increased at the expense of that to seeds or seeds and stems by a single mfp mutation or in combination with uni-tac, af tl, tl uni-tac and af tl uni-tac mutations. The AF and MFP functions are essential in pea cultivars for high yield of grains.The mechanism for simultaneous control of leaf blade and plant architecture suggested by mutant phenotypes has three elements. The MFP, AF, TL and UNI genes exercise control over meristematic activity in all the organs. Their determination of leaf blade morphology and size affect net photosynthesis or metabolite supply. The quantities of available metabolites determine numbers and sizes of organs or partitioned total biomass. The tl allele is identified as a genetic marker/determinant for breeding tendril-less prolific pea cultivars for obtaining herbage and grains in high yields.