Abstract: A genetically engineered land plant that expresses a protein that has homology to a plant invertase inhibitor and/or a pectin methylesterase inhibitor and that increases seed yield with increased expression (“an ISY protein”) is disclosed. The plant comprises a modified gene for the ISY protein. The ISY protein comprises one or more of an ISY protein of Camelina sativa comprising SEQ ID NO: 2 or a fragment, Camelina sativa homolog, or ortholog thereof. The modified gene comprises a promoter and a nucleic acid sequence encoding the ISY protein. The promoter is non-cognate with respect to the nucleic acid sequence encoding the ISY protein. The modified gene is configured such that transcription of the nucleic acid sequence is initiated from the promoter and results in expression of the ISY protein. A genetically engineered land plant that expresses an RNA that increases seed yield with increased expression also is disclosed.

Abstract: A transgenic land plant is provided. The transgenic land plant comprises a putative bicarbonate transporter protein of an edible eukaryotic algae. The putative bicarbonate transporter protein of the edible eukaryotic algae is heterologous with respect to the transgenic land plant. The putative bicarbonate transporter protein is an ortholog of CCP1 of Chlamydomonas reinhardtii of SEQ ID NO: 1. The putative bicarbonate transporter protein is localized to mitochondria of the transgenic land plant based on a mitochondrial targeting signal intrinsic to the putative bicarbonate transporter protein.

Abstract: Methods comprising DNA constructs and polynucleotides of functional transcription factors for improving photosynthetic capacity, biomass and/or grain yield and stress tolerance in various crop and model plants, dicots and monocots with the C3 or C4 photosynthetic pathways are described herein.