Human LAX1 blocking peptide

Adventitious roots (ARs) form from above-ground organs, and auxins are major regulators of AR development. TIR1/AFB F-box proteins act as well-established auxin receptors. Auxin transport involves the PINFORMED (PIN) auxin efflux carriers and AUXIN RESISTANT 1/LIKE AUX1 (AUX1/LAX1) influx carriers. To further elucidate the basis of AR development, we investigated the participation of these proteins and phosphorylation of PINs during adventitious rooting in hypocotyls of pre-etiolated flooded Arabidopsis thaliana seedlings. Mutant and GUS localization studies indicated that AFB2 is important in AR development. AUX1 loss-of-function reduced AR numbers, which could not be reversed by exogenous auxin. Single mutations in LAX1, LAX2 and LAX3 had no negative impact on AR development and the first and last mutations even promoted it. Double and triple mutants of AUX1, LAX1, LAX2 and LAX3 significantly reduced rooting, which was reversed by exogenous auxin. AUX1 was essential in AR establishment, with LAX3 apparently acting in conjunction. Proper phosphorylation of PINs by PID, WAG1 and WAG2 and auxin transport direction were equally essential for AR establishment. PIN1, AUX1 and AFB2 (overexpression) and LAX1, LAX3, PIN4 and PIN7 (downregulation) emerged as potential targets for genetic manipulation aiming at improving AR development.

Though several genes governing various major traits have been reported in rice, their superior haplotype combinations for developing ideal variety remains elusive. In this study, haplotype analysis of 120 previously functionally characterized genes, influencing grain yield (87 genes) and grain quality (33 genes) revealed significant variations in the 3K rice genome (RG) panel. For selected genes, meta-expression analysis using already available datasets along with co-expression network provided insights at systems level. Also, we conducted candidate gene based association study for the 120 genes and identified 21 strongly associated genes governing 10-grain yield and quality traits. We report superior haplotypes upon phenotyping the subset of 3K RG panel, SD1-H8 with haplotype frequency (HF) of 30.13% in 3K RG panel, MOC1-H9 (HF: 23.08%), IPA1-H14 (HF: 6.64%), DEP3-H2 (HF: 5.59%), DEP1-H2 (HF: 37.53%), SP1-H3 (HF: 5.05%), LAX1-H5 (HF: 1.56%), LP-H13 (3.64%), OSH1-H4 (5.52%), PHD1-H14 (HF: 15.21%), AGO7-H15 (HF: 3.33%), ROC5-H2 (31.42%), RSR1-H8 (HF: 4.20%) and OsNAS3-H2 (HF: 1.00%). For heading date, Ghd7-H8 (HF: 3.08%), TOB1-H10 (HF: 4.60%) flowered early, Ghd7-H14 (HF: 42.60%), TRX1-H9 (HF: 27.97%), OsVIL3-H14 (HF: 1.72%) for medium duration flowering, while Ghd7-H6 (HF: 1.65%), SNB-H9 (HF: 9.35%) were late flowering. GS5-H4 (HF: 65.84%) attributed slender, GS5-H5 (HF: 29.00%), GW2-H2 (HF: 4.13%) were medium slender and GS5-H9 (HF: 2.15%) for bold grains. Furthermore, haplotype analysis explained possible genetic basis for superiority of selected mega-varieties. Overall, this study suggests the possibility for developing next-generation tailor-made rice with superior haplotype combinations of target genes suiting future food and nutritional demands via haplotype-based breeding.