Loss of HAIRY MERISTEM 4 modifies phloem companion cell functions in tomato

Catfacing is a physical deformity which is apparent by a cavity like scar usually develops at the blossom end. Owing to scar these fruits render unmarketable hence cause a huge loss to farmer. The molecular mechanism underlying catface deformity is still obscure. Till date no remedy is available to control fruit catfacing. We identified that a CRISPR frameshift mutant of SlHAM4 (slham4CRdelta4) caused 30-70% fruit catfacing phenotype under standard growth conditions. Complementation with 35S:SlHAM4 resulted in complete restoration of normal fruits. We found that the transcriptome of slham4CRdelta4 ovaries profoundly differs from that of wild-type ones, including a substantial overlap with the transcriptome of phloem companion cells. These results suggest that SlHAM4 is essential for phloem companion cell functions during early fruit development to avoid the physical deformity.